Thermal
I use my SGS3 for work every day and it is by far better than the iphone 3GS I used to use and also any blackberry on the market. It's quick and easy to type on (I use the swift key 3 keyboard) and is really quick and easy to do real work on it.
I've used it to access excel files I have on google docs, copy sections of information and paste that into the body of an email so I can give a complete response. That sort of functionality is a nightmare on any of the other phones, but quick and easy on the SGS3. All I will say is you will need to spend a bit of time and read up how to manage your battery life. I now get about 15 hours a day out of mine but when I first got it the setup only gave me about 6 hours, there are loads of good posts and articles on how to sort this out though.
Good luck and you won't regret it