Performance on N5 is consistent with performance on the Jolla. I.E. roughly the same amount slower than Alien Dalvik / Android ROMs. Also much slower than native apps on Ubuntu Touch. It's much deeper than that. They have a serious problem somewhere ...

We'll see, but I suspect it just looks smoother and 'faster' due to new animations and transitions, and maybe further improvements to the renderer. Since the UI started to be overhauled with the pre-Xmas update last year, some load and thinking times have worsened, but most people will probably think it's 'faster' due to better animations ... though the new renderer not suffering from constant and massive frame drops (unlike old one) probably plays a bigger part. It'll be easy enough to tell when the update is released by doing some simple benchmarks on the Jolla (plus I have two of them so I can do side by side) ... I'm not expecting much, as they've never once acknowledged the issues.