I've played both You Go I Go and AUA and they are both very tactically different in gameplay. The advantage of YGIG is that the opposing player is unable to interrupt what you are doing to him unless he has units on overwatch, which in a high powered game, can cause a win within the first couple of turns with a few lucky rolls. The advantage of AUA is that the opposing player can reply to what you do in a very short time indeed, on his very next unit activation. Having played both systems, I do find that they are very tactically different.
For a start, battle plans usually need to be abandoned or adjusted on the fly within the first full turn of play, which means that chaos will ensue a lot sooner.
BrikWars will work well with both systems, but YGIG and AUA do play very differently indeed, and the latter might be useful as an alternative set of rules, as an addendum.