I never had issues with sms nor mms.
Some do - but from what I observe here these issues can be solved like eg over here.
I also never had issues with phone calls whatsoever.
Some phone models seem to suffer from some “echo”-phenomenon at the recipient side. But that’s rare I’d say and I do not remember reading something like that for the two mentioned models.
For both questions it might be worthwile to search the device specific section … or simply give it some more time for answers … 
There are no guarantees of course but I would not expect issues with those two basic phone functions 