An interesting article. The concept of asking to pay for a trial, and a trial of a prototype at that, seems a bit weird for me, though. I don't know I would pay for this. I've come to expect that trials are free, especially of new services.
Same here, beta releases of major games and operating systems are free to select people; and I'm about to do a beta release of my company's first product to which I'll give access for free.
Apologies if this was submitted in the past - couldn't find it after a quick search.