Nice lil joint you got here. I feel more of a Bay Area/Tyga type moreso than an A$AP Rocky type due to the Dj Mustard-esque melody you got going on through the whole thing. All in all, I dig it, definitely banger type potential just keep at it brotha.
This is pretty tight, even though it's not a finished product with vocals and all, it still would be worthwhile to put a limiter or stronger compressor on the master track so the overall volume is more competitive with other tracks on soundcloud, just a thought to consider. As far as the beat itself goes, it's pretty tight. I like the drums and the reverbed out vocals are pretty cool. The arrangement keeps it interesting and the individual parts sound good. Just think about using a little more compression and saturation on some parts to give it more of an in-your-face presence. The ideas themselves are already good imo.
Yeah, most of my beats so far aren't mastered just for the reason of putting vocals in with before mastering the whole track. Would it be better to master them anyway?