[dasil003]

I would be careful with Rails, when you plan to do some heavy data processing and/or if you need your application processes to run for a long time without being restarted.

Heavy data processing yes, but the long running process is bogus. The major memory leaks in Rails were patched up years ago. The tooling is a lot better today on the off chance that you do need to debug a memory leak, and the new breed of ruby runtimes such as Rubinius will keep memory in even tighter control.

[Artemidoros]

Being somewhat problematic for long running process is not only a function of memory leaks.

Even with the better runtimes now available, suggesting that they come close to the stability (and performance and long term memory consumption and profiling + debugging capabilities) you'll find on the big JVMs is not really helpful (JRuby being the obvious exception but even here I am sceptic).