Sorry for chiming in with a semi-commercial interest. I am the owner of USCutter which is a distributor of imported vinyl cutters. We are considering marketing CNC machines, so I was browsing the forums.
In response to the inquiry:
We have just become a distributor of SignBlazer, and everyone that has used the software has given us nothing but glowing feedback. The best part is, you can give it a try before you buy. I haven't used Signgo other than casually trying it out, but my impression is that SignBlazer is much better. We are not selling it directly just yet, but we should be able to sell the Elements (limited version) for less than $100 and the pro version for less than $300. We are also starting to bundle the Elements version with our plotters.
In the mean time, go download the demo version here, and give us some feedback:
http://www.colorchromefirst.com/s2q/intdemodwn.htm