MJ or +? Did you get the MJ or MJ+?
If it is the USB style only, make certain it is plugged directly into the computer, not a hub. This is imperative, as the unit draws the full power from the connection. Even some powered hubs can cause extra grief.
My MJ (not the +) from '09 connects via the USB to the net via DSL (3008/512 IL). The only time it dropped my call was when I exceeded 90 minutes at one go to that number. Otherwise, it works quite well. Voice quality better than my cell; almost as good as POTS.
I would never trust it to replace my home line, or for 911.
For very economical LD calls, I have no qualms about the unit.
Never tried their tech support. My understanding is more people have had problems with the +, and tech support is 'an interesting experience'. In another thread, a query was raised if there was a prioritizing of the data the router was doing. They also like to block exchanges, which I'm not thrilled about.
Where did you get the unit? Would they take it back?
Faxing with this thing is a crap shoot, at best.