"It depends on what your priority is- Reserve card gives you MQM on purchases and trumps on upgrades.
You could save $300 and go with platinum and still get some MQMs and admittance to Sky Clubs for $20 a time."
The Delta Reserve Card does not give MQM's on purchases. It does give 15,000 MQM's after reaching $30,000 in spending and gives double regular miles on Delta purchases only. With the regular Amex Delta Platinum one can enter the lounge for $25.00