Should I install ruby 1.9?

I've updated rails to 2.3.2, should I update ruby to 1.9?

What are the advantages/disadvantages in doing so?

Ruby 1.9 is the new kid on the block. It's where the future of ruby is headed and at a basic level is faster than ruby 1.8.x. Not everything is ready for it yet though (while rails is, your code or gems that you use may not be ready yet).