We self host internally, and the biggest problem we have is our internal/DMZ network structure. It's a horribly complex beast, and usually quicker to access moodle off site! Having said that, it has got a lot better since we installed a speed tester on it and discovered the server had a driver installed that twinned the network cards on it (which was doing more harm than good) and rejigged it. And IT have installed faster links between certain infrastructure points.

In terms of manpower here we have the equivalent of 2 FTE support staff (I'm one, the other is split between two people hours wise) and where we need expert Windows/technical help (or co-operation) IT are usually willing to chip in where they can (and actually paid for our server, as they were convinced all the speed complaints were due to the age of the old server - which wasn't quite the case).