I have only used Embird and it does not digitize.
It is very easy to use and I cannot imagine being without it.

I also have Embird - no experience with Buzz Tools (not really much with Embird, either!) Embird has a plug in for digitizing called Embird Studio which doesn't cost much compared to other digitizing programs, and most of the people I know of who use it swear by it! They love it more than the expensive proprietary software.