I came close to buying the same model tractor you are looking at back in 2012. Because I use the loader a lot I decided on a 4wd instead. If you don't plain on doing much loader work you should be ok, just be prepared to use a good sized counter weight. These tractors are a little crude and noisy compared to others, but they are bang for the buck. I've had a few issues with mine, but nothing major. ( Lack of dealer support mostly.) I read a comment saying that the 50 series was a 100 hp tractor with a 50 hp engine. I think that's accurate. It appears to be old school overbuilt. Check the gear ratios to see if they work for you.
Based on comments from other owners QC may be an issue sometimes, for different years. I personally don't regret my decision.