I just got this gas block and installed it so that I can put my DD Lite 9.0 on.  The gas block was pretty cheap $25 shipped on eBay.  It's one of the cheapest ones out there, but has anyone had good or bad results with the gas block?  I'm about to purchase some Federal XM193 and I'm kind of worried that the gas block might move on me when I shoot at the range.  They have two set screws that screw at the bottom, and from what I had read it's not the best mounting system; not sure if this is by real world experience or not.

I have one just like the one you describe It got approx 800rds of various ammo and I have never had a problem with it or the screws loosening. I own quite a bit of YHM poducts and they are all GTG in my book

got mine under a DD lite rail 12" , zero problems with it!!!

I used one in my last build. I put on my 16" mid length gas, under a rifle length YHM lightweight handguard.

Works perfectly! fit very nicely

Got mine with a YHM Spectre kit. No problems after about 1k thru it

I have one as well under a DD Lite 9" & it's no different function or appearance wise than my Stag low pro. It works great. Bear in mind that there are MANY low pro gas blocks that utilize the two set screw on the bottom of the block. It must be working for some. Thread lock the screws or pin it if you're worried about it coming loose.

Thanks for all the replies.  I feel better, because I was having second thoughts thinking I should've gotten the Larue Tactical, but that one is $70!  I've spent enough money over there, so at least I saved some money on the gas block .