BM can be used for data logging too, it has an optical interface for that. The adapter costs ridiculous money, however. OTOH, there are DIY implementations.
This UT is a good meter with favorable reviews, but my gut feeling tells me, maybe wrongly, that UNI-T meters in general don't really belong in that segment. They are (or rather used to be) best bang for buck in the $50-ish range, but of these two I'd probably pick the BM.
I actually own a BM869s. It's a good fast meter, however there are some minor annoyances:
- slow update rate (1/1s or so) in the AC+DC mode (and in some other modes, where it doesn't really matter)
- usable bottom range of capacitance measurement starts at ~100 pF
- autoranging in the resistance mode could be faster: I have to fix the range when I need to hand-pick matched resistors from a bunch, for example
- no LowZ voltmeter
- can't test white (and blue, at least some) LEDs: test voltage is just not high enough
- occasionally, pretty rarely, at power-on into the DCV mode, it's stuck displaying 0.0000V until the selector is switched to another mode and back -- and this glitch is a recent development
Overall, it gives a feeling of a platform that shows its age. It needs a facelift. Nothing critical, however. And its continuity beeper is hands down awesome. And the bar graph is actually useful: while I don't use it otherwise, it can show if the measured voltage has ripple at a frequency beyond what the primary display can reflect.
Another feature worth mentioning is its CREST mode: peak detection within, I believe, a 0.8ms window, to capture events that the regular min/max mode won't detect. Can be used to measure short pulses or Vpp of an AC waveform, up to a certain frequency. Can also be used to measure inrush current, with a shunt, without using an oscilloscope.
Oh, and it uses the 9V battery, none of that leaky AA/AAA crap. Works perfectly on those rechargeable 2s LiPo packaged in a standard 9V case without an output step-up converter.
It also has big ass fuses that cost a fortune and all the requisite input protection circuitry, of course.
I don't know if the UT is better or worse in any regard. I wouldn't mind having both, I guess.