Hey guys - sorry, I've didn't read the whole thread. I'm using the V6 since 3 years and quite happy with the solution. For german speakers you can find here my findings.
https://www.a1k.org/forum/index.php?threads/58280/
I haven't tested the latest updates of the firmware but I got the best results with 6.2.1 - so there was no need for me to go further. (sync 8.5MB/s) In my experience are the following points crucial: