I've been using this for just about a week now... also a DFB customer.
I've already done my review, but one concern that has come up since then is that the profile names aren't "real names".
I haven't checked all of them, but in all the profiles that I've spot checked, the profile name is something like "xsdhdfhksdf". My guess would be that as a forum admin, these type of accounts are quick to be deleted without even giving it a second thought.
Setup some sort of random name generator to create better profile names, and this problem would be solved. The admins won't be as likely to delete the profiles.
IMO, it's the little things like this (and the log in service) that people are probably going to be willing to pay more for with other services like DFB. If you guys can deliver on equal levels, you'll definitely give them a run for the money.