I've been using 17.04 as my daily for a bit over a week now and it's been very good for the most part. I haven't had any issues with startup or shutdown time variances but a couple little issues have carried over from 16.10. Most notably the icon sizes on the top panel aren't always correct (Inhibit applet, Steam, Clementine, etc) but no big deal breakers. Here's an image showing the icon issue with the inhibit applet and Steam.
