I actually worked for the company Home Depot uses for their cabinet refacing program for a brief period last year. It's a one-call close environment, so be prepared to make a decision the day of the sales pitch.
Cabinet refacing works best with certain conditions. Are you happy with the current layout of your kitchen? Are your cabinets in good shape? If it's yes to both, then refacing is an option.
Completely replacing the cabinets might change the footprint on the floor, making new flooring necessary, and would also involve getting a new countertop. Refacing can be done without affecting the flooring or countertop, and is less disruptive than replacing.
One good thing about HD is that their salespeople offer one price and that's it. No haggling, no dropping the price (unless it's a change in material) to make the sale that day. The "be-back-in-touch" rate in that industry is very low. They will go back out -- I even remember going back out to one customer's home who called back, and was told that was the only time anyone in this area's ever heard of that happening -- but they don't like to since it means two trips for one customer instead of seeing another customer and a chance at an additional sale. I do know from personal experience that HD's prices are cheaper than those from another national retailer's, but not sure how they're going to compare with the local contractors.