Unfortunately, there really isn't a great alternative. The next best thing I've found is to just run your own mail server, which is pretty obnoxious if you have any non-technical users to support. Kerio is the thing which most Mac shops I know use (since people want directory services and the other stuff you can't easily implement just from open source). Yet, there's better search on server on gmail than from iOS to IMAP (i.e. Kerio), so that's a sacrifice.
I kind of hate Google for being the Craigslist of email -- a crappy product at $50/yr which sets the maximum price people are willing to pay below the point where anyone can offer a less crappy product. More like $250-$500/yr/mailbox would be a supportable price for real email.