It can work both ways, if you absolutely know the work you have is "one of" a one time deal whereas once done the machine will sit, consider renting.
On the other hand, ownership has advantages, though a rental you don't have to perform repairs, own something decent and you have it to your avail and its usually worth it for that reason alone, both dozer and rubber tire backhoe are handy, I think you'll get more use out of the backhoe, what I find is the best combo is like a ford 545 D, industrial tractor loader, put a 3 pt or heavier hoe on it, 3pt though light, you then still have a 3 pt for implements, its wise to get the most use out of a machine by virtue of how its set up, won't sit as much and does more things for the same price.
For clearing and grubbing, a dozer in the wrong hands can make a mess, cut the trees and try and de-stump the area can make holes, you lose valuable top soil, ideally a root rake and a non 3 way dozer blade, just push arms will be a lot stronger for heavy work. A backhoe though on tires, you have to watch for things projecting, you can get more use overall and still do some clearing and grubbing, use the hoe to take stumps out, knock the soil off. Bucket to grade, sometimes you need both but the backhoe will do more tasks, add a set of forks, thumb on the hoe, little more versatile.