I agree: Tracks 5 is very nice.
I never used the TR4 standalone more than once, but I've been playing around with the TR5 standalone all evening, and I really like it: sounds
very good, workflow suits me fine, new metering is great, and I enjoy using it. Performance is fine for me, too. So far, it is stable, loads up quickly and I'm not experiencing any issues with lag, sludgy performance, or whatever.
I can see areas for refinement and adjustment, but for what I do, I think the Tracks 5 standalone is going to be really useful.
As for the new plugs - I think they are excellent, especially One. And the revamping of the GUIs on the older plugins was long overdue and very helpful, especially the changes to the presets dropdown menu. All in all, I'm quite glad I invested in the upgrade. For me it was totally worth it.