Does anybody have any hands on time, preferably long term, with the UTG Pro Super Slim in either Keymod or MLok?  I was able to check one out on a rifle briefly in a shop but a few minutes of holding it doesn't tell you how it'll hold up.  I was really impressed with the feel of it and so far I can't find anything bad about the UTG Pro series in online reviews.  I'm just having a hard time getting over the "UTG" name but I have seen repeatedly that the UTG Pro is a big step up.

It looks like it's just as capable as the SLR I was originally considering minus built in QD, 6061 instead of 7075, and about an ounce heavier...at less than 1/2 the price.

UTG Pro is good to go as far as I'm concerned. Made in America. The machining quality is right up there to the BCM KMR. The fit and finish are higher end as well. Only recommend upgrade would be replace the factory screws to better ones from McMaster Carr.

That's what I've seen too.  Specs on the screws you used?  In the 16 page UTG thread I read through I thought I saw them saying there were two different screws depending on if you're using the original super slim or if it's Keymod/MLok.

I have two recent production Pro Super Slim MLoks and have had no issues with either the rails themselves or the screws.
I did have barrel problems which required me to remove the rail off of one rifle and I reused the same screws when I reassembled the rifle. I used blue Loctite on the screws and tightened them down tight and the screws were fine, no stripping or breakage.

for the NON recessed KeyMod/Mlok rails you would use Hex drive flanged screws