I really enjoy dvorak and I'm glad I switched but I can't say that the difference is enough to justify the pain of switching. It took me a long time to get used to dvorak. The first few weeks were very unproductive and it took me many months before it felt natural and I was faster than before. But I find it really comfortable since about 80% of the letters I type are on the home row. The benefits of dvorak are less when you're programming because there's a lot more punctuation and dvorak is mainly optimized for English words.
I'm not sure of the relationship between dvorak and repetitive stress injuries. Your fingers travel a lot less with dvorak, so they are doing less work. But I'm not sure if it makes any real difference.
