"the full version will cost $24.99"
I wonder how that will boost uptake?
Runtime Revolution Livecard [
http://livecode.com/download/ ] has a two-tier system; a commercial version which protects the developer's code when s/he spins off a standalone,
and an Open Source version without that protection. Their uptake has increased immensely since they released their Open Source version, and there is demonstrable
uptake of the commercial version by people after using the Open Source version for some time.
The presence of an Open Source version means that a lot of people are prepared to spend a lot of time bug-hunting and reporting which accelerates their development team's work.
They release a beta version on average every 2 to 6 weeks.