|so i should get the AA and not some evil pip kit?|
Two things to consider before making a barrel purchase:
1. How much do you want to spend?
2. How many guns can you use it on?
If you don't have the money for a kit, then you get a single barrel. I do think a kit is worth saving up for, though.
A 7 piece kit in anything but autococker threads would, IMO, be a poor investment if your tight on cash. You're going to be locked into a particular manufacturer.
However, that same kit in cocker threads would probably be a pretty good investment. You can use that same kit on lots of markers. Pretty much all markers use cocker-threaded barrels except those from Smart Parts(Ion, Nerve, Shocker, Impulse), WDP (Angel), Kingman (Spyder) and Tippmann (M98, A5). Older ICD markers have their own threads, too.
I haven't used the evil kit, and I've avoided their products because of their marketing. However, as I said previously, I can heartily recommend the Redz kit (and Redz gear in general... fantastic stuff) and the Freak Kit.