I'd highly recommended
@ghilliebear2000 for any build! His (Jeff's) builds for me have been outstanding and he's so easy to get ahold of, willing to help you with any issue, and pleasant to talk to. IF things don't get stupid next year it's my plan to have him build two or three more kits for me, that's how confident I am in his builds and proud to own them. Loop
As with
@esh21167 the PTR's have been available here and there but unsure, as I'm not a PTR man, if they suffer from the non-conforming BCG when it comes to locking pieces and such. I just remember a friend having a full size and bummed when his new locking piece was a no go.
As for Omega... Just no. I'm a short distance from their facility and see their guns quiet often in pawn shops or on a bench for "tuning." I've been on the range in person to see their UMP clone literally separate into two pieces and a few of their MP5 copies fail any sort of full day at the range or even make it through ammo tests without issues. I honestly have no clue how they are in business with their history and most people locally do not favor the company nor their owners/family (even those who use to work with them!).