The new gmail interface is excessively busy, difficult to use, and overall is just a bad user experience. Multiple scrolling windows in one interface is bad enough by itself, but all of the changes combined make it a productivity killer. It also seems to have gotten much slower of late. I’m currently testing multiple desktop clients to replace it. If you have a favorite, let me know.
In the meantime, if you are staying with gmail, here are a couple of alternatives. None of them were good enough to make me stay in the web interface though.
Gmelius is a poly-browser extension that proposes a better and cleaner Gmail™ inbox. – Addon for most browsers
Cleaner Gmail – Extension for Chrome