Well if the price is about the same, I'd go with the
Paiste. The Signature series
Paiste cymbals are absolutely beautiful to look at, sound great and are usually super expensive... Depending which model it is it could be warm with lots of washy overtones or dry with great stick articulation, i could have a great bell or a dull bell. The Signature series can be used in pretty much any kind of music--a lot of rock and jazz players like em.
You know, each cymbal sounds different, even within the same brand/series/model. You really need to listen to them to make sure they sound the way you want them to.
The AAX is gonna be a bit cheaper at retail, and will be thin like the Signature
Paiste, just not as pretty visually and will sound different--a lot of metal and rock players like em, especially in the brilliant finish.
Other than that, its all about your personal taste in sound--I can't help ya much there.