makerbot has the distinct advantage of having open-sourced a (largely) physical product. For me at least, paying them for the bits and pieces to put their printer together would be an order of magnitude less effort than compiling and installing some software downloaded from the internet. They still offer a valuable service in manufacturing parts, and hence don't have to just sell support to make a living.
This is a great feature of open source hardware! Arduino has shown that there are plenty of platform plays in the physical world. The MakerBot builds on the RepRap mostly, and makes money doing the leg work of getting the parts to you easy / quick / cheap. Now the tons (10+ projects?) of clones coming out build on this platform.
