^ I personally don't understand the "must use Fluke" for mains mentality. If DMM doesn't work, then I obviously won't use it on anything.
BTW, if this is the same model (I bought mine last week) you have to open the housing to put the battery in, so I've already given mine the once over.
Insulation from mains is pretty easy. Are probes and leads covered in plastic? Yes? Is the housing of the DMM made of plastic? Yes? Ok, I'm good. Lol. 120V is not scary because of DMM you use, but the safety protocol you employ. Wear shoes. Don't touch bare wires while they're live, and only one at a time when they're not.
If my DMM catches fire, it's ok. I don't carry it in my pants while using it. It's hard to read that way.
There are plenty of mains devices that I use every day which are not made to Fluke standards. While I'm measuring mains (with any DMM), I'm at least aware of it for the seconds or minutes for this operation. If I have to probe mains once in a while, I am not going to buy a Fluke. (I actually have got a Fluke for free and have never used it.)
If several hundreds of volts or if I do this day in day out, maybe I start being more particular.
Basically, you should be more scared of shoddy wiring in things that can start a fire while you're asleep than the quality of your DMM. IMO.