I wouldn't dog the feature like that... PayPal is only the CURRENT option... We first start with a BASE then work to ADD to it... Otherwise the dev cycle would be MUCH much MUCH longer... I'm sure you can count on authorize.net and many others in the future...
Well, THIS site is for user to user support; we only know what we're told and what we've learned about the product... The official support section is the Groupee support desk.
As for what features where added, it's a no brainer, the ChangeLog is there, and Rick does a fairly efficient job of adding what he throws into the product into the changelog... You just have to take the time to actually go in and read it...