I have both.
Obi is just bridge and require some setup to hook to google voice/third
party service through Obitalk.
Ooma is one box, turn it on and it just works.
For elder people, Ooma may be better because it require no work at all.
Obi/Google voice works most of time, but if something mess up (networkwise),
one may need to delete the google voice from obitalk and reconnect google
voice to obitalk again. Anyway, that does not happen very often but it
occurs two or three times for me.
Anyway, my parent had obi/google voice, then ooma after hearing obi no
support google voice, but when I asked them to move back obi/google voice a
couple of months ago, they said they prefer ooma because it is easier to
setup after a network outage.
