I don't recall ever seeing anything for voice calls, and such a thing would probably be illegal, but I've seen numerous people talk about and test data "deprioritization" between main carriers and MVNOs. If lots of people are using lots of data bandwidth on a main carrier, someone on an MVNO may get their data speed reduced during that time.
...
With respect ... its the same old internet chatter about "deprioritization" "between main carriers and MVNOs"
The people making these comments that you read are ignorant to what all carriers do. One just needs to read the disclosures from the "main carriers" and they will see the same type of wording.
Any network, any cell network can slow down under heavy traffic, even your local cable internet connection to your home. It makes no difference if its a MVNO or Main Carrier. Best part is IF, IF the MVNO is not to your liking, there is no contract, so just like you buy gas for your car anyplace you want, you can switch carriers anytime you want. Try doing that with a "main" carrier that you signed a contract with.
Just discussing here, not debating, Ive been using MVNOs for over a decade now and cell phones for the last 20 years, now in EVERY corner of my new state since 2006 and border states, they worked just as good as my work supplied Verizon iPhone.
I have never, ever had an issue with my personal MVNOs and that includes Straight Talk from Walmart, Walmart Family, Cricket Wireless and my current ATT RedPocket which I have had for many years now. One other thing about me is I am a bit anal about things working perfect and I NEVER settle for less.
Anytime I switched was just for better pricing, though technically, whether one can tell the difference, Redpocket ATT service on speed tests is the fastest and same as main network service.
For the life of me, I will never sign a contract for phone service, the only reason people do is to get what they think is a "free" phone from the main carriers.
Again, read any cell provider disclosures and "terms of service" for some reason, people who do not use MVNOs are compelled to point out the "terms of service" for the MVNOs but not the main carriers that they use, its all the same wording.
Ive posted it and the links many times in forums... but tired of spending the time doing it *LOL*