First of all, it's insanely fast, I was really impressed how fast it's opened facebook, and its minimal interface it's awesom.
But I think there are some issues:
1. I love the maxthon's drag and search, but in Nitro 1.0.1.600 there isn't.
2. I don't like much the link preview, sometimes it doesn't appear and sometimes it's a bit laggy
3. I think the close button (top right) is too small, but its invisibility it's amazing.
Anyway, programmers are doing a great job