I was actually rather surprised how hard it was to get some genuinely good, solid info on the current state of broadly useful Geiger counters which are neither garbage, nor priced exclusively for Governmental Bodies.. Heres what I found out, It took a week of on/off deep digging about, though heres three notable options I found, and view as about as good as it gets, which may help save you some time too 
No: 1 - Radiascan - 701A - (£292) For doing semi proper analysis and measuring Alpha radiation as well:Notes: Russian made - Will ship them anywhere and also have a US warehouse and Will ship from Cyprus (EU) in 2021.
Order here:
https://radiascan.com/User Teardown of one here:
https://www.zielonyatom.pl/radiascan-701a/(The one I went with)
The Good Stuff:* Has a switchable cover on the back to allow selective measurement of Beta, Gamma and Alpha Radiation (cover removed).
* Reliable, FAST,
accurate, highly sensitive metering across the entire range from virtually nothing to standing a little too close to Chernobyl.
* Has a number of automated analysis functions aimed at things such as assessing food contamination and windowed averaging of measurements for area assessment.
* Proper data logging with usb upload to computer.
* A screen and UI thats comfortable to use and displays just enough info at anyone time.
* Will charge your batteries (nimh) via the usb port.
* Updateable software/firmware - actively maintained by the makers.
* Pretty much government agency grade performance at a price most serious hobbyists can afford.
* Great customer service in dealing with them directly, also extremely fluent in English.
The so so Stuff:* Internal battery life is merely 'okay' - 55 hours with the oled screen set to standby, 10 hours if you leave the screen on 50% all the time.
* The Alpha capable Geiger tube is going to be more vulnerable to mechanical mishandling damage than standard Beta/Gamma only tubes.
* Honestly cant see why they didn't go with AA or generic Lithium as a power source.
* They recommend on setting the oled display to 20% increase the screen life to a claimed 16,000 hours and to increase battery life if left on all the time.
* Would of much preferred a switchable backlight Transflective LCD like that seen on the excellent iGPSport bicycle computers. (amazing battery life & screen longevity).
No: 2 - Terra P / P Plus - (£150-175) Best as a general purpose Personal Radiation Monitor:Notes: Ukrainian made - Available from various sources.
One Such eBay seller:
https://www.ebay.co.uk/usr/dosimeters_radiometers_countersDocumented and sold commercially here:
https://ecotestgroup.com/products/terra-p-2/
The Good Stuff:* Compact and robust personal monitor.
* Reliable, FAST,
accurate, highly sensitive metering across the entire range from virtually nothing to standing a little too close to Chernobyl. (truly one of the only cheapish ones that actually is)
* A large number of them in use by serious governmental & scientific institutions - proven and tested (also loved by a slew of 'radiation nuts').
* Incredible battery life off 2 AAA batteries, will sit there and run on a pair constantly for 6-8 months (allegedly).
* Removeable tube cover to do some basic calculations of radiation composition ratios.
* Even fancier models available if you want to spend more for things like phone linked data logging/upload.
* The two most recommended models, the P and the P+ differ in not much other than some extra minor features, if you need them.
* {customer service unknown, though people don't seem to be having issues}.
The so so Stuff:* Its only really useful as a general purpose personal safety monitor / spot check tool - but it does that VERY well.
* The user interface is somewhat fiddly & lacking, but then you wont need to use that much, to be honest.
* Doesn't detect low energy Alpha particles - Although its quite rare you'll see them just by themselves at dangerous levels.
* Data logging is internal only in this particular model.
* Not updateable - but then, it doesn't need to be.
* Its not quite a lab instrument - but is that your use case ?
No: 3 - DIY - SBT11 Based Geiger Counter Kit - (£75) A particularly reputable open source DIY kit maker:Notes: Lithuanian made - Available from designer, Arturas.
Ebay Shop:
https://www.ebay.co.uk/usr/impexeris?_trksid=p2047675.l2559Makers Blog Here:
http://arduino-geiger-pcb.blogspot.com/Current Product Sale Link:
https://www.ebay.co.uk/itm/Geiger-counter-dosimeter-kit-assembled-w-SBT11A-tube-iR-USB-Arduino-compat/164235169256
The Good Stuff:* A really cheap option - (and looks to be far better implemented than a lot of the £30-50 garbage thats out there).
(Also, you sort of get the functionality of the Radiascan, but on a slim budget)
* Open Source and very hackable.
* This version of the kits (SB11) detects Alpha radiation with the window open.
(Seller stated in emails that its better for this than the SB10 due to thinner mica window and compact sensor)
* Highly sensitive, seller calibrates them and takes making them seriously - so it should be somewhat accurate.
* Time required to reach an accurate count in lower dosage situations unknown, though the developer seems to have put the work in.
* you can build it into any manner of housing and battery configuration that pleases you.
* Supports data logging and connection to PCs as a detection peripheral.
* Possibility to collaborate / contribute to the ongoing development of this project.
* Design has been out there at least 9 years now.
* Customer service great, fast and really helpful; also speaks good English - (spoke at modest length with them).
The so so Stuff:{all of the below comes with the territory of diy, frankly}
* Whilst partially assembled and calibrated for you - you will have to find/make housings for it & determine how it is to be powered.
* Speed/Accuracy isn't certain - However, given that its open source, it can be calibrated/improved upon as needed.
* its going to be one of the bulkier options in its current incarnation, but still much smaller than the Chinese diy kits.
* Geiger tubes run at 400v & the supply is capable of 1Kv - mind those fingers, it will bite - enclose it properly.
The Other Options - In Summary:Practically everything else ruled out due to the following:
Commercial:* 'True' professional options ruled out as the price tag attached to them was up in the sky - (institutional budget target)
* Many Cheaper models (some with misplaced good reputations) aimed at personal monitoring/budget institutional use where shockingly bad in Accuracy/True Range at Top and Bottom of the emissions scale and failed to get middle ground measurements right (quickly) - largely only useful in reality for telling you that you where somewhere exceptionally bad and you should go now, mkay ?
* Some pretty bad interface design sometimes.
* Some had proprietary batteries for no good reason at all.
Used:* Anything thats really cheap is ancient - for better or worse.
* No warranty, not easy find parts for most of them.
* Old stuff is gigantic, or barely dependable.
* Sensitivity/Accuracy either due to design of the time or aging/misuse can be shockingly bad.
* Lightly contaminated meters are 'fuuuun' ..good luck with getting that background reading count down
* Newer stuff worth having tends to either go quickly, or not be much cheaper than getting a new, warranted item.
DIY:* An awful lot of terrible junk around in the £50 ish range it seems, which at best has not had the tube drive voltage set correctly, count rate calibrating & prone to also being slow to get middle ground counts right, if at all.
* low and high count accuracy dependant on choice of tube and count capability of the microcontroller/firmware.
* Might be able to get ok results with one of the ultra cheap kits, but really should calibrate and verify it against a known good commercial meter.
Cheap ready to use Aliexpress/eBay China Stuff:* Some of it might look the part, right down to niceish looking user interfaces. But when it comes to something that might be your
personal safety on the line, I just plain don't trust them to care about getting it right (rather than merely sold) based on mixed bag experience with certain other items of a similar nature and 'complexity' in the past.
BONUS CONTENT:Heres a comprehensive, complete and information dense extract from a book concerning radioactivity in the food chain following the Chernobyl event which I stumbled across in my research on these matters, its downright fascinating.
Also useful information if something {tin foil hat} as unfortunate as that happens again in the post readers lifetimes - in any case, a great set of data points for things to be somewhat concerned about (and not) in moderately relatable situations:
https://www.intechopen.com/books/radiation-effects-in-materials/radioactivity-in-food-experiences-of-the-food-control-authority-of-basel-city-since-the-chernobyl-ac