I wouldn't touch UTG rails. I consider rails to be a critical component. Cheap rails may simply break, may not be aligned perfectly straight. I remember buying a Leapers bipod (Harris clone) that was terrible and was returned within days. I've had some other disappointing cheap stuff which is why I am a lot more careful buying accessories now.
I don't knock all the cheap stuff. My VFG is a Promag grip that cost me $8.95. My SHTF rifle is built on a DPMS lower and a Model 1 upper and internals. None of those components has contributed to a single failure to feed, fire, or eject. However, I felt it necessary to get a quality fore-end and BUIS, which is why I have an MI rail and rear sight, and a LMT bolt carrier. All my scopes, other than the Leupold Mark IV that I got for free (and the EOTech, but that's not really a scope) are cheapos.
Troy, YHM, Midwest Industries, LaRue, you're not going to go wrong with any of them. Anything that contributes to accuracy or reliability, I don't skimp on.