I've tested ATT/VZN/T-Mobile, currently on T-Mobile.
With Verizon (when I was testing it, I was seeing -110 to -115 in buildings) and even outside only rarely did I ever see 4-5 bars.. A friend has a Verizon iPhone 6 - I see -108 dbm on this friend's phone, 7mbps down, 1mbps up. I test with T-Mobile similar signal but 25mbps down and 5.8 mbps up..
Do Verizon iPhones have issues picking up LTE?
Anyone here have 5 bars on LTE with Verizon -- if so, how often?
It would be interesting to know for folks with iPhone 6 and 6s' in particular if you bring up the dbm meter in the top left corner:
http://www.cultofmac.com/128306/access-the-hidden-field-test-app-for-iphone-ios-tips/
Then note what type of signal you see and where is your phone when you test it?
For me:
T-Mobile: average: -102 to -107 (main floor/basement) LTE (speeds generally 20-30mbps down, 5-10 mbps up almost all of the time)
Verizon: -102 LTE to -114 (main floor/basement) (8-12 mbps down, 1-2 mbps up when peak)
ATT: -102 to -108 (main floor/basement) LTE (2mbps down, 1mbps up when peak)
--
When driving I see AT&T and T-Mobile consistent 4-5 bars (and -68dbm or lower (in the -60s))! For Verizon I only once saw 5 bars when I was about 30ft from a tower. Really? When driving I'd normally see between 1-3 bars of LTE and it was always changing between those 1-3 bars. Where as with ATT or T-Mobile the LTE generally stays at 3-4 bars of LTE driving the same route.