I have just purchased a dynavin unit myself after much deliberation, they are very popular with BMW owners and MB users across the pond. I havent had chance to fit the unit yet, but will be doing so in the next week or two.
All I can say now is the unit feels very soild, the tactile feel on the buttons feel as good as those on my audio 10.
I wouldn't expect much manafacturer support but the units seem well recieved by those who have them.
I will post my musings for the instalation and operation of the unit when i get the time to install it.