Otherwise you will be always be running an outdated version of all gmail services and there is no real benefit really in having gmail handling your MX.
What features are you using in Gmail that I'm not getting in Google Apps? I have priority inbox and all the latest Labs experiments. I haven't heard of anything I'm missing.
Also, if you have an android phone you cannot buy apps if you sign in only with your apps account, you must use a regular account. That is a PITA, believe me.
Now, you have the hassle of having to deal with multiple account on your phone, but is not too bad. It comes bad when you discover that if reset your phone and sign in only with account A or only with account B or even in the wrong order (B, A), all the apps you bought are simply gone.
Yes, the market sucks that much.
I've found a little lag in gmail to apps features, but not long enough that I've worried about it.
http://www.google.com/support/accounts/bin/answer.py?hl=en...