Played around with aberration on 3 occasions.
First time with FutatsuNoOmoi, on Candleburg. He was an Infiltrator, and didn't really do anything, but just adding that. I had gotten level 6 aberration, and had stacked it on several things. No lag.
Second game, a public, 3vs3. Map was Kedges.. I can't remember the class setups anymore, bleh.. However, I do remember the game lagging so much very soon that I couldn't play. Futatsu even had lagged a lot.. In fact, everyone in the game but him and I (I just watched his screen) bailed out and left before the game was over.
Third game, another public, 3vs3. This time on Candleburg. Again.. Lagged like crazy, same results as the previous Kedges.
So.. I've played a lot, but hardly played with aberration.. 2 out of 3 games playing with it, I believe it's a cause for memory leaks.