My 5er came with one 15K AC unit and prep of the 2nd AC unit. We did add a heat pump for the 2nd unit in the bedroom. We are wired for 50 amps.
The times we have run on 30 amp I have had to watch our power consumption and put the hot water heater on gas otherwise if my better half turns on the microwave while the AC is running, I have to go reset the post breaker. The idea that you just can't turn on everything on at once, like an home, is a difficult concept for her. 50 amp service makes my life easier :D
Get the 50 amp service. When you need it, it's nice to have.