The choice of model is dictated by the carrier you're going to be using.
First determine which carrier has the best signal where you need signal. (And that means at your desk, not only in the street in front of your building - a dead spot can cover as little as 2 feet, so if the phone works fine out in the street, but not at your desk, all your incoming calls go to voicemail and you have to go outside to place a call. The same thing where you live - in any room in which you want the phone to work.)
Then you choose the model for that carrier.
The V20 doesn't bootloop by itself, but any phone rooted incorrectly, or having something wrong flashed to it incorrectly, may bootloop. (I returned mine because after just a few days I grew to hate the phone, but there was nothing wrong with it technically (except that the Recowvery root no longer works).