The web mail doesn't include tagging or inline conversations but otherwise it's pretty good with not too much wastage. Of course you also have IMAP/POP access if that's your flavour.
I don't miss it at all though - I find that 99% of my email needs are on desktop and mobile, and the native clients on just about any such platforms are more than a match for GMail.
I still have a webmail client I fall back to - nothing quite as good as GMail, but that's more for when I need to look something up on a public terminal.
On the flip side - I gain an unhijackable account. Worst case scenario they make off with all of my information, but I never lose ownership of the account. I also know my server's backup policies, so short of cracking my host wide open they can copy my data, but never destroy it.
The only consolation is that google apps do run a version or two behind, so it is probably better tested and have most problems nutted out.