What to look for when buying a dozer

[newbury]

I originally was holding out for a nice JD 350C because it did not exceed my towing capacity.

I ended up buying a CAT D3 because I found a good one... My only negative or plus is that I can't move it. It's a plus, because a lot of "Friends" have asked to use it until they find out how much they will spend moving it.

This is one of the critical things which I'm concerned with in my noobie thread. There's a tradeoff being able to easily move the tool yourself versus getting the biggest tool.
Sure a 170hp dozer may push over trees a foot to a foot and a half thick without too much effort. But my 6hp Stihl will take them down also, and in my case I've darn few 18" trees I need pushing over.