F = Fear. Yes: Today is not a good day to die.
U = Uncertainty. No:
We know what goes into meters, and we know why those differences make professional meters cost more than cheapies.
D = Doubt. Yes: I doubt the accuracy of a meter that doesn't come with a NIST-traceable test report, can't be calibrated, often doesn't even include useful specs in its manual, and may well be outside the specs it does claim.
I use these on high voltage circuits all the time.
I'd hate to be your insurance underwriter.
Now, as a general rule, I don't poke around in high voltage circuits (with any meter), instead, I prefer to hook up a pile of meters to everything I am interested in and then turn it on.
This isn't always possible or practical.
Within our audio DIY field, yes, it usually is practical, if inconvenient.
But, professional meters are also used in power plants, on working HVAC equipment, etc. You can't turn off a building, or a power plant, just to make a single test.
You don't know what
else the OP will use this meter on, after he gets done building one of the circuits we talk about here.
the $6 meter is considerably safer
You can do the same thing with an expensive meter. In fact, it's often easier, since you likely have a good set of grabber clips for an expensive meter, whereas adding a decent set of grabber probes to a cheap meter often exceeds the cost of a meter, so those who prefer to buy cheapies often eschew the good probes.
Yes, probe quality matters. A good probe will have a larger, better-insulated handle, made of material that isn't likely to crack and expose the internals. It will have superior ergonomics to keep your hands from slipping down to the metal: tacky silicone instead of PVC, broad finger shields instead of slab-sided cylinders, wider bodies to add increased insulation and avoid hand cramps, etc.
That said, in a decade of working on tube amps with 500V+ power supplies, I have never had a meter fail due to voltage within its specs.
One of the things we use meters for is to probe voltages we
don't yet know.
We use meters on equipment that has failed, or isn't yet working correctly. We can't know what the voltages are until we use the meter to find out.
If you've never been surprised by a reading or gotten an overload indication, you've had a pretty narrow band of experience.
the various B&Ks cost a lot less than the Flukes and seem to offer similar specs.
I've had mixed experience with B&K gear.
I've got one of their LCR meters here, and it works great. I've also got one of their all-analog bench supplies here, and it's a joy to use.
I've also got one of their signal generators here. It's so disappointing that it went back into the shipping box within a year of buying it, and sits in that box to this day. The sine wave function has ~2% distortion, the square waves ring, and the whole device has scarcely better build quality than a DIY project. I'm pretty sure the internals are DIY-project quality, too. It's probably just an
ICL8038 in there.
Caveat emptor.
I've never used a B&K Precision DMM. If they built it like the LCR meter I have, then yes, it's probably trustworthy, both in terms of measurement and safety. But, it's not going to cost you $6, either. Their cheapest meter
costs $32, and it's probably an outsourced Chinese ODM design that you could get elsewhere for cheaper. The stuff they actually design and make themselves will cost considerably more.