Looks great! But I won't update anytime soon. The reasons are:
ST4 won't surpass in sound quality
- TT SD3 for drums
- NI, Ample Sound and Impact Soundworks for bass and guitars
- XLN AK2 for grand piano
- Waves keys for EPs
- NI Session Horns and Magix Independence for pop brass and horns
- KH Orchestra, NI VSL and SoniVox for orchestral instuments
- AiR for synths
- IK ST3 for compact all-in-one rompler
Besides sound quality not being on par with the best instruments on the market, it will take 500GB of disk space (250GB for the sounds, and ~250GB to keep archive available off-line in case you need to re-install it but your download has expired and you need to pay more to download your sounds again).
But it looks like a great investment for those who are new to collecting software instruments. In other words, if I didn't have all other libraries and instruments, I'd bite on the new ST4. But I do, so I won't.