Like I've said before, I actually really like UG identity (at least in cube). The problem is that its very picky about what types of cards it wants in the card population; but the basic aggressive formula of getting ahead on mana development, so you can play fatties with counter and bounce backup, is a lot of fun. Both colors provide evasion (flying/trample) and you can always add a touch of blue card draw, addressing the issue of your aggressive decks running out of steam. Just make sure you have that foundational ramp, and the decks very nearly build themselves. (elves/bouncelands). Its frustrating that there isn't more depth, but at least the basic formula is engaging.
All of the colors, I think, could be described as having both aggressive and controlling characteristics, which is significant. What matters is how those elements are layered over one or the other. For example, you're never going to get a reactive UG deck, due to the lack of hard removal: reactive elements in U/G will always result in a third color removal splash, making attempts to support those strategies in UG effectively a wedge/shard endorsement.
B/W really frustrates me, as most of its strategies feel like they lose to U/x midrange or control decks: like B/W is effectively executing the same gameplan, but with worse tools. Than in the aggro department, its fairly miserable due to the lack of reach.
Reactive U/R is kind of interesting, because I feel like its probably the worst of the reactive U/x color pairs (UG aside of course), since the removal is never really consistent. It can run into that control deck problem where you just draw the wrong part of your removal suite to match what threats the opponent is spinning out. It can still produce competitive decks, but I feel they are on average worse than what UW or UB can produce. Its a shame too, because the X spells in red (and blue), dovetail much more eloquently into what a control strategy should be (mana superiority fueling endgame abuse), than anything black or white provides, which is largely just mercenary removal spells.
Its kind of funny that the aggressive slant is basically a fun burn deck, but I will allow it.