It's a good start but I can't use it yet. It is too S-L-O-W and I am running it on a Nexus one with a confirmed (via speedtest.net) D/L speed of over 3 Mbit/s
It seems to load your list of current emails every time you open it or change accounts and it takes about 30 or more seconds to to this, probably uses more DATA than necessary as well.
I also don't like that I cannot have a signature for each account. I use my Google Apps Gmail account for business, a different Gmail account for personal mail and a POP3 account for spam/junk and I need to have a completely different sig for each one.
I DO however like the ability to have a different color LED notification for each account and the rules settings are nice as well. I may have to try this again after some changes are made, until then the default apps do everything I need them to and they are waaayyyy faster.