How were you running your Rails app at TextDrive, lighttpd/mod_fastcgi or Apache? What kind of problems were you having?
They run all the rails stuff on Lighttpd/FastCGI. It was absolutely horrendously unstable.
The site would go down after a mild spike in traffic -- 500 Internal Server Error -- and stay down until either I manually restarted Rails or my Cron job did. I had to have a Cron job running every hour to make sure that my site was still up because it was going down so often.
In addition to that, TextDrive has something that they call "the Samurai" -- a watchdog that kills any process that's consuming too much CPU time. In an ideal world, that would prevent a buggy app from slowing down all the other apps on the shared server, but in this case what it was doing was killing any popular apps at peak time!
There's a long post about it on their forums; I started it when I was still a TextDrive customer. By the end, I had gotten so fed up with the utter instability of Lighttpd that I had become a DreamHost customer.
I'm not using any Rails applications right now but I always figured I'd run them at TxD if I need one because lighttpd performs so much better than Apache. To keep things on-topic, there's a suggestion posted for DH to install lighttpd. Vote for it if you need it!
No!!!!
Sorry... I just had flashbacks of staring at 500 Internal Server Error pages because of Lighttpd... 
I used to think that Lighttpd was better for Rails sites than Apache. It's true that if everything is running perfectly, Lighttpd is faster than Apache for Rails apps. However, what they don't tell you is that Lighttpd is horrendously unstable. You simply can't depend on it. It will go down on you the second you start getting a moderate amount of traffic (say, around 2,000 page views a day).
The only thing Rails hosting on TextDrive is good for is learning. That's it. If you try to run a real site on it, it will blow up.
Believe me -- the guys at TextDrive are really nice, but their Rails hosting sucks. It's ironic considering that David Hienemeier Hansson and the creators of Ruby on Rails call them the "official" Rails hosting site. I guess they had to make money off of Rails somehow. 
You can read my thread on the TextDrive forums here:
http://forum.textdrive.com/viewtopic.php?id=10972&p=1