Re: services
The most important question is does he have (or plan to buy) equipment that requires 3-phase? Creating 3-phase from single phase is not an optimal thing to be doing. Very large motors typically are generally only available in 3-phase, and 3-phase motors are more efficient and easier to start than single phase motors.
The next is does he need voltages that are commonly delivered as 3-phase, such as 480V or 277V? Many industrial light fixtures are available in 277V. I don't know if a power company will deliver you 480V single phase if you don't need all 3 phases.
If he has no plans for 3-phase equipment or voltages, then a service of given KVA will use smaller wires (and less amps per phase) with 3-phase, but it will have one additional wire. Or stated another way, a 200A 3-phase service will have about 1.7 times more power than single phase for the cost of one additional wire.
So to me, its not really a pro-con issue, but whether you need that type of power for your equipment.