It depends.. is it a "handheld" or a thermal dongle your pursuing..
since you mention the HT19 I reckon it's the handheld you'r going for.
Personally, I would not go for the HT19 in 2022.. which I reckon is still sub 9hz.
For a decent handheld in 2022, I would look at GuideSense models.. like the PC210 or PC230. which seems to be a tad over 300.
It's a 256x192 sensor and is obviously smaller than 320x240 and the Guide PC210/230 unit also has a smaller screen, but the picture seems better even with less resolution..
There is also the UnitT260B, but from the looks of it, the Guide PC210/230 does seem to deliver a cleaner picture.. both 25hz if I recall (don't have either, as I prefer dongles)
Check Youtube.. gives a decent insight into the experience you will encounter with these.