I am currently hosting everything with midPhase, and previously, I hosted with ANHosting (which is part of the same company as midPhase anyway). The only reason I'm ad midPhase instead of ANHosting now is that I took advantage of an offer to bump my overall package up a little, and then combined 2 accounts, since none of my sites are very high traffic websites.
That said, one annoyance I've had since merging my 2 accounts appears to be caused by the confusing (I think) practice of using the php.ini and .htaccess files combination to make sure all sites are routed correctly (for me, 4 small sites).
Because of that, I thought I'd look around again to see what else is out there.
One thing I noticed with Site5 is their ... +Turbo package which has one particularly intriguing piece, in my opinion. They allow you to use the same tool that the Hosting Reseller packages use, and that is an account management screen, and total separation of each site/account. So instead of using .htaccess rules and such, you would just use their web interface, and each site would then work like its totally separate dedicated account.