Step7 V15 Professional can program all PLC's, but offers nothing extra over the V15 BASIC if one plans to use v5.6 for the other PLC's anyway.
My understanding is that v5.6 will program 300, 4 PLC's, and the V15 (TIA) is needed only for the 1200 PLC's. So I'm planning to get the Step7 v5.6 BASIC and the Step7 V15 BASIC. Due to all the (still) missing basic functionality in V15 (TIA), I don't plan to start using it any sooner than I have to.
