Yes, I know this topic has been beaten to death, but most of the threads I've found are either very old or have devolved into shared vs. VPS flamewars, so bear with me.
I've got a project coming up where I'll be setting up small WPMU-based sites for a couple handfuls of niche communities. Ideally I could persuade everyone to get a cheap VPS for this purpose, and I will definitely be recommending this strongly, but in the real world we all know that some people just won't do it. So what I want to do is compile a small list of shared hosting services that are known to work well. Traffic and resources really aren't my concern -- I'll let them worry about whether their service can handle it or not -- my concern is whether I'll be able to get it up and running with a minimum of headaches.
My requirements, outside of the standard WPMU requirements (Apache, mod_rewrite, wildcard DNS, etc) are SSH access and Subversion. Based on what I've learned so far, my current list of known-good hosting companies is:
* Textdrive
* A Small Orange
* Media Temple
I have a Textdrive account and will verify it works there myself, and will attempt to do it on Dreamhost. I don't have access to any other services and so am relying on the community for input here.
If we can get an up-to-date list going I'll add it to the Codex, which will make life easier for a lot of people in the future. Thanks.