I own a 790 but I think the 43xx series tractor are one of the best combinations of power and size of the newer Deere tractors. I've recommended this machine to two friends, both of whom are very happy with their tractors.
Before I got my 790, I looked at a 4300 (sync shift with 280 hours). I really liked this machine but decided it was too big for my needs. I had never realized how close in size the 790's were to the 43xx machines. The 43xx tractors are quite a bit heavier then the 790's though.
Considering the low hours, I think you are looking at a really good deal!