I'd go with clickteam too.
Games Factory is waaaay too old though, I don't think they'll even sell it anymore. They offer two great products called MultiMedia Fusion and Jamagic.
MultiMedia Fusion is an event-based system (like Games Factory) which means that you can make a game on pre-defined events (e.g. when object X <collides> with object Y then do <action>) which you can alter and link together just with a simple mouseclick. It's quite flexible and you can almost make any game with it.