I have Amplitube 4 and TH3 (it's 32 and 64 bit compatible https://www.overloud.com/node/26/compatibility) I can get good sounds from both (there's nothing like a real amp set up though, imho). I lean towards Amplitube 4 more but I think TH3 is cheaper for some of the packs they sell ($89 for the Roc...

I've been using EZ Drummer for quite awhile. You can get good sounds from a lot of expansions using multiple outputs and applying eq and fx. Also love the song arranger and midi libraries. With that being said, I did the upgrade to Superior Drummer 2 and loved the sounds and how you can tweak stuff ...

Sonar refugee here too and haven't had alot of time working with Mixcraft 8 Pro, yet, but will. Does anybody know if RX6 works well with Mixcraft? I haven't had a chance to try it yet.