I think as a hand held scope its not bad. There are not too many between what Dave calls 'toys' and usable hand held scopes. If all you need is a DMM, you can get one cheaper with the same specs, so the extra cost is for the scope part.
I don't own one, but had to choose between it and the Velleman HPS40. The 40 is on closeout at Tequipment for $200, and the 81B is available to USA buyers only via eBay for about $180 S&H included, from HK or China.
There are a couple of youtube videos reviewing it looking at old analog TV waveforms, and likewise there are a few reviews of the HPS10. The both the 10 and 40 has been around for ~ 10 years, and was popular as a budget automobile scope, but the frequency response for such work is under 1 MHz.
The 81B review is very revealing, because old PAL or NTSC color burst signals require a scope in the 10-20 MHz range. Those signals in the video look good enough, and they are typically 4 MHz bursts. The 81B specs state it has a 40Msa/s rate, which suggests its only useful to 4 MHz, which means its should roll off thereabouts, but the signal on the video looks pretty good.
The HPS40 is a competitor, and I've tested it to 4 MHz with distortion, 2 MHz is clean, so its more like a 3 MHz scope. Its sold as a "12" MHz handheld, and does 40 Ms/sec too.
http://www.amazon.com/review/R2A7O3DS27XQVA/ref=cm_cr_pr_cmt?ie=UTF8&ASIN=B000WCCVBC&nodeID=&tag=&linkCode=#wasThisHelpfulThe only problem is having to buy the Uni-T from China, vs from the US, if it breaks within warranty, tequipment has a very solid reputation.
I think the Uni-T is a better bang for buck in paper, if it could be purchased locally and if I could really see it at work.
What do I use it for?
You have a high risk of damage to your scope or injury to yourself if you read AC line voltage, or any portion of it even if stepped down [ unless its fully isolated first] or what you think might have AC line voltage as a contaminant, using a AC line powered scope like the popular Rigol 1052E. Battery powered hand held scopes are not physically grounded, but float, so its ground is relative not earth ground.
The Velleman is built very much like a Fluke 80 series DMM, and rubberized. I've looked at waveforms as high 1kV DC using it [which surprised the jeebers out of me, as I wasn't expecting to see it nor did the Fluke 87V pick it up, except it was suspicious because the readings never settled down to a solid number], and while it doesn't have the best screen for examining waveforms, it tells you that it is there, riding on the DC or low voltage AC. Its easily to lug around, and very easy to see in sunlight, the HPS40 LCD is old type the HPS10 is sharper and clearer but not as fine as the Uni-T [particularly a version sold with deep blue pixels], but the HPS10 is only rated to 1Msa/s, that just 100kHz response.
Anytime you want to take a quick peak and see what type of a waveform could be in a test circuit, the Velleman or even the Uni-T if I had one, can deliver; the only question is accuracy of the shape because of its frequency response, but once I identify something else exists in a test circuit, I have the option of setting up a better scope and taking the DUT for a better exam.
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