It would be interesting to hear longer review. Still I believe you experience is better than OpenMoko FreeRunner (I have not owned it but my coworkers and other people I know bought these and never used again). This experience alone discouraged people from trying anything else.
It would be interesting to see if one of those Open devices or OS succeeded but it needs more than "open" for that.
These are just the developer devices. The first Firefox OS devices sold to end-users in Brazil will be manufactured by ZTE and/or Alcatel. (Note: I am a Mozilla employee, but I don't know anything about the Telefonica devices beyond what's been publicly announced.)