I'm still out. $49 upgrade and I'll buy...
Song designer is ALA EZKeys, which I like. With EZ, Eco, BFD2, BFD 3, Session Drummer, SD, and SS EX...and all the kits I have...I'm pretty well set.
Swapping Kit pieces...no big deal (for me) and not worth $99 dollars.
And when you can buy SD right now for $99 and have all this (just about) and more...
AND the upgrade path to SD3...It's not a good deal, unless you ONLY own EZD 1.
While the song designer is a good idea, not a prerequisite...