The main advantage of a 64 bit vs 32 bit VST is the amount of RAM it can access.
No need to return Mixcraft! because there are what is called 'bitbridges' to help you with your 64 bit VSTs
There are several bridges available if you google 'bitbridges for VSTs' I chose jBridge as it seems to be the most popular (and the cheapest). I documented my adventures with jBridge here: http://forums.acoustica.com/bbs/viewtopic.php?f=14&t=12251
On my soundcloud link on my signature, 'You Know When the Music Stops....' is done completely with bridged 64 bit EWQL PLay and bridged 64 bit Kontakt.