I don't know anything about HomeVestors, but will give you something to think about regarding any franchise.
When you buy a franchise, you are buying name recognition and advertising. Everyone knows who Subway is, no one knows who Bob's Super Awesome Sandwiches is. The number 1, 2, and 3 question that you need to ask is, is the name recognition and advertising worth the cost? The franchisee is going to give you a game plan, but is it really something that you cannot go learn on your own?
If name recognition + advertising + the business plan is greater than what you can do yourself, then the franchise is worth it.