I'm actually on the same setup (Ubuntu 10.04 x64) and I haven't had any of those bugs. I didn't import bookmarks at all (using the same profile from Opera 10.11) and it's much faster than Firefox and Opera 10.11. Chromium is about on par in term of launch time but is slower in term of page load speeds. I've only been using this since yesterday when it was released but I haven't seen a bug so far.