I have had no issues with them. I have been using the Obi110 since the beginning of this year. I have used it with the following SPs: Voipo (of course) as well as Viatalk and Voip.ms.

I love the call routing/bridging features as well as the auto attendant. I currently remap some of the star codes to make it easier to remember. (i.e. *255 (BLK) maps to *27 and *732 (REC) maps to *2. I also have my office line fork incoming calls to the obiapp on my desktop and phone so I can use a softphone or a regular handset.