Originally Posted by
NHFL9
Yes you can check bags when arriving at T4. There is a full service Delta counter, SkyPriority lanes and all.
As for when to leave the lounge. Not sure. We arrived at T4 last week 90 minutes before our flight and we're very glad we did. No priority security lane and the checkpoint was one of the worst managed checkpoints I have ever been to. Despite a medium length line it took us 40 minutes to clear the checkpoint!
As for which lounge is better, I have only been to Oasis, which is quite nice. Can't comment on the other one.
There is a priority lane at security (not a SkyPriority lane), but you have to be confirmed in Business or First (and have that on your boarding pass) to use it. It is hit or miss, even at the same time. I've had a flight leaving in the early evening and ran into the same mess that NHFL9 describes. I've also left at the same time and had almost no one in either line. So there's no way to know.
I'll be glad when DL opens an airside lounge in May 2013, but T4 has it's own issues that DL will hopefully address.