I'd recommend getting a Obi 200 or Obi 202, since more service provider slots is good. I have an Obi 202, with all 4 slots filled. In my opinion, the Obi is a good mix of fairly easy setup (harder than Ooma, but still pretty easy) and flexibility (much more flexible than Ooma and such).
GV is not going away; it just requires a different (OAuth) authentication method, which is easy to do if your Obi is up to date. On newer Obi units you can also use
Ring.to for free voice calls; opinions on
ring.to vary.
If all you want is E911, Anveo is pretty cheap at $0.75/month IIRC, but you have to put in $20 at a time. I had Anveo for several years for a DID (incoming number) and E911. Their pricing for unlimited person DID is pretty good, but you don't get CNAM (Caller ID name lookup).
IIRC Callcentric has free DIDs in certain area codes, and it's popular service for Obi users.
VoIP.ms is another popular service provider.
I ended up dropping Anveo since I have 2 other E911/911 providers and ported my Anveo DID to
Ring.to (the porting was free and quick). My Obi doesn't support
Ring.to, but I've had GrooveIP for a long time. I haven't had any major problems with them. Neither
Ring.to nor GV support CNAM.
Ring.to can port in land line numbers, GV won't (you have to port to a cell phone first).