BlackDragon put this very nicely. If I could add something... If you wish to have a really nice 3D Printer that you will learn to upgrade quite easily, and that you don't have to worry about spending a ton of money every few years, the RepRap is for you. If you are more interested in having a solid printer that does what it says it will do, has a great support service, and is ready to print as soon as you get it home, then MakerBot is for you.