I like Chrome's UI a lot so I don't mind Firefox becoming that. However, god damn it I just want a good browser. One I don't have to restart on a regular basis. One that doesn't become sluggish after a day of usage, or 20 tabs open.
Firefox right now is an overall sub-par experience. Of the two, it's the only one that I've seen actually crash (Chrome has individual tab crashes). The scrollbars aren't stylable and it is a lot slower.
And then Chrome has its own issues as well. Its "Restore tabs" dialog is too easy to click away (firefox's is a lot better) and it just loses the tabs. Not to mention when there's a lot of tabs to restore, it loads everything at once instead of doing lazy loading like Firefox. And Chrome still doesn't have autoscroll... I use an extension for it, but it can't touch the chrome:// pages...
These are all extremely long standing issues, it's incredible they haven't been fixed. Fat good that competition between Mozilla and Google is doing.