Indeed. GMail has quite poor usability even when compared to other web clients - massively wide lines of text across the whole screen are really difficult to read. We got over this for regular websites when suck.com popularized snake text in the early 2000s. Why does gmail still use it?
I was actually trying out Chandler earlier this week and I found it disappointingly hard to configure, and I'm not normally one to have that be the show stopper (cf occasionally spending 10 hrs figuring out how to build some unixy software and have it interact nicely with some sort of emacs package)
I just end up using Mutt as my MUA and Gmail as my really fancy sorta-half-MDA. To finish it out I have to use something like fetchmail (which is okay), I usually end up using Mutt's built-in imap feature.
Gmail easily beats the old-school bunch, but the quantum leap of email is definitely still ahead of us.