I looked at Bull Dogs, the problem I found is 1. to much money for what you get, 2. don't think that warranty is set in stone. The dealer by me doesn't know a tractor from a VW, didn't know the back wheels could be adjusted, or anything about the hydraulic's at all. A friend of mine bought a Bull Dog and it has sat 2 months waiting for parts, this has happened to him twice in 3 years.
Me personally, I wouldn't pay the extra money, it uses the same engine as Jinma and Kama.
I think you could do with a 35hp tractor, but I would buy a Kama, Jinma or if you want bigger ,a 40hp Foton (farm pro) or Kama.
I have 72 acres and 35 hp would do fine here and so would a 40hp, depends if you are going to run bottom plows or not, if you are going to run plows I would go with a 40hp, but a 28hp will pull 2 bottom plows, I have done it no problem.
The jump from 35 hp to 40 hp is a big jump is size and might be hard to move around clearing trails and such with a 40hp.
The bottom line is, no matter who makes it you will have to work on the tractor at one time or another, I would rather work on it myself then someone who doesn't know a tractor from a VW and just had enough money to become a dealer.
Check out Artrac.com
, Chip is a good dealer and deals more than one brand and has good prices. Ask Chip what he thinks he knows.