Checking out the new features offered in V15, other than Groove Agent SE6, I had very little interest in them and felt I would be fine with V14 for a while.
But, curiosity got the best of me and I purchased the upgrade a week or so ago. Just got around to installing it and working with it some.
I was pleasently surprized: The overal performance, at least on my system (Ryzen 7700. 64gb RAM. Windows 11 Pro 25H2. RME Babyface Pro FS) is noticeably better than V14. Maybe as much as a 7 to 10% improvement. The interface is smooth, snappy (and so far) very stable.
I would just like to thank Steinberg and the Devs. Nice job