We usually skip over minor version upgrades, but Z3TA+ from Cakewalk is a very special synth, and 1.5 is a very nice (free) update. New in the version bump: x64 and Vista support, a low-CPU arpeggiator (assuming it’s handling voicing/oscillator resource allocation more efficiently?), different CPU-optimized quality modes (also added to rival NI Massive recently), and more.
But it also features two additions I wish more synths had. First, there’s MIDI file import for the arpeggiator. It’s a no-brainer feature, and yet most arpeggiators don’t do it. Why? I have no idea. (Any fave synths that do, please add them in comments.) Second, smarter MIDI learn features per-control min/max/reverse, and user-definable configurations so you can switch from one rig to another without manually remapping. Again, why this isn’t on every single piece of software you use is beyond me. Details and free update at Cakewalk.com.