I resisted buying one for years, but now I have one I'll never go back to a pan - even though it was fine at the time. I generally use the cooker for japonica grains (koshihikari or Akita komachi) and the results are noticeably better than what I could get with the pan.
As to which is the best, it depends on where you are (and how much you're willing to pay). There are some amazing machines in japan, different technologies used including some that will wash your rice for you. The top of the range machines cost between 500 & 1,000usd and then there's the cost of the transformer and shipping.
I'm very happy with my EU Sanyo model,
Similar to this one http://www.japancentre.com/items/2674 which was under £90 about a year ago but with the exchange rates...
many people swear by their Zojirushi branded cookers. If budget is a concern, I'd recommend looking in to the Cuckoo brand as the Koreans are just as passionate about getting the best out of this style of rice.