737 Professional V Pilot in command

They are both different, as they model two different series of 737. The 737 Pro is the older 737 Original (737-200 ADV), so there is no FMC and a more rudamentary autopilot, old fashioned gauges, etc, where as the Pilot In Command is the 737 Classics (737-300, 400 and 500) so have the semi glass cockpit, new autopilot and full FMS system. So i suppose it depends what you're most comfortable with. The old school 737-200 or the more modern 737 classics.