SAP explicitly warns against using mix of client and component releases - basically stay with revision 6x for Studio when on SPS6, and use rev 7x only for SPS7.
My wish list for now would include Netweaver AS 7.4 trial on SPS7; as I'm heavily into ABAP-related developments on HANA, the added benefit of having a Netweaver stack running on top of HANA makes it the ideal package. Guess that won't happen for the foreseeable future...
Regards,
Trond