No regrets! Ruby has performed well for us and we've almost never had issues due to Ruby or Rails itself in many years of hosting and building, so that's great!
I do have two things I wish were better though:
Ruby should be further along than it is now in terms of low-level maturity with things like memory allocation and garbage collection and JIT compilation type features. It feels like Java and .NET are a decade ahead in the fundamentals.
There's a general lack of emphasis in the Ruby community on overall "performance as a feature". We've tried to help with rubybench.org