"Choosing" Sorenson isn't a choice. It is an unreasonable expectation for the deaf users out there to:
a) Be trained and expect to remember how to operate 2 different devices to get their equal access
b) Not be used with other kinds of relay services -- that means that your friends with TTYs can't call you on VRS, they have to get their own VP to talk to you.
Given these things, there's no way consumers will be able to avoid getting Sorenson VP-100's if they are not good at using technology. If you don't understand IP addresses, and are stuck in the past with phone numbers, and most of your friends have VP-100's, you can only get a VP-100.
If they understand IP addresses or technology, I would say they tend to go with freedom of choice and get a D-Link or both and put up with the limitations that having both devices put on them.
