I wrote an earlier, positive review of WindowFinder, and I am writing another one here. Yes, Witch is free, it works fine, and it will suit many people's needs. But I cannot use it because I already have a host of keyboard configurations that make Witch impractical for me.
WindowFinder works just fine, and I have found the developer to be highly responsive to feature requests. This program is a viable option and should be given its due as such. If the developer asks for a shareware fee, so what? Shareware developers should be allowed to profit from their efforts if they so choose. The price for this program is not astronomical. If you don't want to buy it and use it, fine, but again, at least evaluate it on its own merits.