Anyone considering Verizon instead of T-Mobile I would assume is disappointed in T-Mobile coverage in their area (otherwise why go to Verizon?). This will only lead to frustration down the road. And hopping between carriers should not be taken so lightly, especially when there are a ton of hidden fees from Verizon and AT&T every time you sign up for service (trust me, I learned the hard way).
If you want to test whether T-Mobile service would be good enough for you, do that on a separate phone with a separate account and a separate number. You don't want to be in the position of needing to re-sign up for AT&T or immediately switching to Verizon because you realize T-Mo coverage isn't good enough for you (and again, if it is good enough, why are you switching to Verizon?) 😵