An AMEX Platinum card gives you SC access + priority pass lounge access, but through "rebate" promos you get $200 credit from flying plus $100 Dell credit every 6 months and other promos "every now and then"
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This is probably your best option if you're planning to fly DL a lot, want lounge access, and aren't flying SFO-JFK all the time. This would also get you into the Centurion Lounge at SFO if you're ever flying out of T3.