Originally Posted by
DCAproducer
This is probably the best advice. Pretty much anyone boarding in the last zone should be ready to potentially have to gate check their bag. Spending a few bucks for the C+ will get you more leg room, better boarding and free drinks domestically.
You also asked about valet (plane-side) bags. DL does this on regional jets. These are bags that get a "pink" tag. These will always be delivered back to you when you arrive. Some regional jets such as as the 170/175's do fit carry-on bags and don't require the pink tag. You'll never see plane side pink tags on a mainline aircraft.
"A few bucks" is a little generous. Delta has really blown out C+ pricing (if it is even available at all, which it usually isn't unless you're booking more than three weeks out). The domestic routes I fly price C+ $150-200 higher than Main Cabin and $200-250 higher than Basic Economy round trip.