For me, AD2 falls third on the list, being
BFD 3 - nothing compares right now...
Superior Drummer 2
AD 2...
I don't think people truly realize how significant AD2 is...it is far more versatile and usable
then EZ2....don't get me wrong - EZ2 is GREAT for Song Writing...but soundwise it's
far to limited...and TT just gave you new graphics and MIDI, not entirely redone samples...
which XLN did do...
On the top end - BFD 3, SD 2, SSD 4 Platinum
Middle - AD2 - it falls in between because it gives you more (full) tweakability then EZ2-
(which is vastly limited)
Low end - EZ2, SSD 4 EX
Session Drummer falls under these...and the Chocolate Cake Drums...they're not worth much...
unless you're a heavy Session Drummer user..
That's my rankings....YMMV
Mind you, if you just want to slap drums on a track and be done....that changes things.
But most do quite a bit of tweaking....as presets never quite give you what you're looking
for...and that is why I rank them this way...