I bought it yesterday and really like it so far. New layout is great, and love the new Chord Pads feature. This is something I really wanted a while back. Anyway, since I just got it yesterday, I haven't been able to dig any deeper, but I was able to open my latest VSL project and it played back without any issues, and mixdown was flawless. It does seem faster (snappier). As for audio engine efficiency, I opened this project I have, which always gives me the dreaded "CPU Overload" message when I do a realtime mixdown wth a low Asio buffer, and it survived much longer than previous versions, but I still got this message at around 17% (before it would fail at around 4%). This happens because I use my Virus TI synth as my external USB sound card.
All in all, I didn't regret my buy! 😊