I had the gear drive conversion on my '03 wideglide. The only thing I've noticed is that they are noisy (like Glider mentioned). I would go with the roller chain if I had it to do over.
I was told by my dealer that the tensioners were not a problem until 30K miles or so. My rear tensioner was shot at around 10K miles. Personally, I would do the roller chain conversion for peace of mind if nothing else.