i have the mbr1000, only these issues I have. One, the latest firmware 1.31 sucks. Stay with 1.20. The other issue is I could not get opendns to work on mine. Don't know why really not a big issue for me.
I use sprint 3g with it and had no problems at all. I got it to get rid of comcast. Yes this is my primary connection. No problems using it as the main net connection.