I use Maxthon, which uses the IE engine. Love it to death. I use to have Firefox has a secondary browser. But once Opera went free, it got put to the side.
Finally I had a go of this new version. It appears a lot smoother. The menus, the configuration dialog - much faster. Especially when you click Ok to save what you have changed. But, the amount of resourses it uses is just stupid. I want a browser which uses less than 15mb, not 80+. So with that memory leaks still there, I uninstalled it again.