I happened across a random tweet from Jesse Noller about free hosting on Rackspace Cloud for open source projects back in July and immediately requested an account for Factor. It took me awhile, but I just finished moving most of our services to the new machine. We've been hosting on Linode since 2007 or before, and while it's been a mostly positive experience, disk space used to be tight so we had to move the binary downloads to Dreamhost, but even then their unlimited disk space seemed to fill up. I will be moving downloads to Rackspace soon to complete the transition.
Working with Rackspace Cloud is super easy. I've created three machines so far--a Linux web server running Arch Linux for hosting the website, an Ubuntu Linux build machine to do 32/64 bit builds, and a Windows build machine for 32/64 bit builds. When you create a new machine you can select its region, whether or not you want a public static IP, and the CPU/RAM/disk space, via a slider. The machine comes up in a couple of minutes and you can ssh in with root access (!) and configure everything.
It's nice to have the build machines running in the cloud instead of heating up the office, and it's great that Rackspace supports my favorite distro, Arch Linux. That leaves me only with one physical machine, a Mac Pro for 32/64 Mac builds. Factor's build farm will be once again fully operation within the next week as I get time.
Cheers to Rackspace and @jessenoller for supporting open source!