You've never had to choose one unexpected opportunity over another? It's never easy, but I think you should probably cut them a little slack.

That said, I'd probably see if I could figure out how to pay someone else to run Go Test It. I have no idea how well the service was doing, though. It seems like maybe not that well if it's worth dropping. :)

--edit-- Oh, I had no idea Go Test It was a Red Gate product. Now I'd like to 2x my first paragraph up there. Quitting a job because something you own is gaining momentum is (a) exceedingly normal for this group and (b) what any rational person should do.