robtillaart:
Arduino is a project but sparkfun is a company, not sure about the other 3, it sounds a bit like comparing apples and pears. The open nature of the last option can give you a dozen names that might be meaningless to you so how would you classify them. So the value of the answer is restricted in its use.
Yes, i am trying to compare apples to pears 
- or rather, looking on different approaches to open source hardware development.