I have to say, given a choice between them--between Great Commission and Great Command churches--I'm more inclined toward the latter. Here's why:
I could get into some philosophical and innately theological reasons for this--you could draw off of thinkers like Martin Buber (who said things like, “All actual life is encounter" and “When two people relate to each other authentically and humanly, God is the electricity that surges between them.”) and off of Bonhoeffer's theology of "place-sharing" (most notably examined and explained by Andrew Root in his book Revisiting Relational Youth Ministry) in order to get there. But I'll simply say that it's because the former is in danger of losing itself by way of losing the latter--we can lose the command to transform lives by losing the command to love people. The secret of the Great Commission is thoroughly embedded in the Great Command. We have no hope to change people without loving people and we have no hope of loving people if all we want to do is change them.
It would be tragic if we failed at changing lives simply because we failed at loving people--but it would be far worse if we succeeded at changing lives, even without loving people. If we're not "converting" people by way of love, then to what on earth are we converting them?
And we are called to take up our cross--to love as Jesus loved. Great Command churches are in danger of loving people in order to change them and thereby limiting love's freedom. Great Commission love is at risk of being love for change's sake. We don't have to stress out if people don't change, it doesn't mean we've failed. If we can simply love people, we've done our job... and that's where the Great Commission comes from. When we've actually loved people, then we can invite them into the life of love that we're living. It's more difficult--we have to leave our value for effectiveness at the door and trade it for faithfulness. We have to simply love and then just trust that something will happen. We have to trust that love transforms.
Don't try to transform lives. Instead, love people... and trust that love can transform.