Here's why a 4" well is far superior to 2"....
The submersible pump...
will never freeze
will never lose prime
is water cooled and completely sealed. No bugs to get in the motor, no worries on hot days, and is a lot easier to hide.
Twice as efficient. My rule is thumb is that a jet to submersible is a 2x deal. In other words, a 1-HP jet would be equivalent to a 1/2 HP sub. Actually it's a little more efficient than that, but 2x makes it simple.
Much quieter. I doubt you will even know it's running unless you're really paying attention.
Just in general lasts much longer by my experience.
The only advantage of the jet pump is that they are cheaper to install and the pump can be serviced without pulling the whole drop-line. On the downside you'll have a jet and leathers/footvalve down in the well that will have to be replaced periodically. Also, since the motors are not sealed and are air cooled they are much more likely to get critters up in there. I have found small snakes, lizzards, and countless dirt dobber nests. Not uncommon for the well to lose prime after the power has been out for a few hours.