I have seen people talking about adding a NetTalk Duo to their Obi. For those considering it this might be a good time to order. You can't add the credentials directly to the Obi but this could work well for those people that have an Obi110 or Obi2xx 3xx series Obi with Obiline adapter. I am currently using a MagicJack with my Obi202. This type of setup gives you a low cost provider with the extra power of the Obi. According to them the NetTalk Duo VoIP is also "fax friendly". Once attached to your Obi it can be set as your primary line or it can be used with a dialing sequence.
One of the reasons this might be a particularly good option for some is that NetTalk has an add on plan that gives you unlimited texting for an additional $29 per year.
NetTalk Duo VoIP Telephone Service :
Free calling to the US & Canada or Duo to Duo
Ultra-low cost international calling rates
First year of service is included; $29.95 for each additional year
Live US-based technical support and personalized customer service
Free 411 directory assistance,
enhanced 911, visual voicemail, call waiting, conference calling, conference bridge, and fax friendly
Sales ends 2/20/14http://www.frys.com/product/6792695