I went with buying and colocation because I found I sleep better this way than when I used to rent servers in a distant datacenter and have to count on techs I'd never met working on hardware I'd never seen if anything went wrong. In my case, I live near the datacenter, so I can be hands-on fairly quickly if something goes wrong that I can't handle remotely.

And I can do whatever I want with the hardware. When I bought my servers, they came with disk controllers with non-optional RAID, as almost all of them do. I wanted to run RAIDz2 in FreeBSD/ZFS, so I swapped in non-RAID controllers. They were just a few bucks, but having that ability meant I could choose from a wider range of servers.