My family attended the CLB for a few years in the mid-80s, jumped ship for about 10 years, and again attend there. My oldest brother went to their High School (Hillcrest Lutheran Academy) in Fergus Falls, and he worships at an LB church in Moorhead. There is some variance in practice, to be certain. At least in my hometown (Maddock, ND), the church has always been more involved with the Evangelical Free congregation in Esmond than with any local Lutheran congregation (even the one on the other side of the parking lot). As is common in the Hauge-derived churches, it's extremely low church. They're very strong on foreign missions and the inerrancy of scripture. While I believe that they subscribe to the unaltered Augsburg Confession, they don't tend to emphasize sacraments very much. Insofar as ecumenicism is concerned, my impression is that they are somewhat cloistered when it comes to other Lutheran congregations. One potential weakness that I have seen is a predisposition toward what I call "Lutheran Baptist" theology (basically, decision theology) which once again undermines the Lutheran understanding of salvation and the sacraments. In that sense, they can be something of a paradox.
Bear in mind, this is just based on my experience with one small congregation. There's a great deal of congregational autonomy in the CLB, so my experience may not (and is very likely not) indicative of the practices of their synod as a whole. That being said, I think if they made an ecumenical move toward the ELCA, the devil would probably start shopping for hockey skates.