Glad to hear you're enjoying DL, and congrats on getting upgrades as a silver -- that's pretty rare these days so don't necessarily count on it for all your travels. But yes, Delta keeping exit rows outside Comfort+ is definitely a nice perk for lower-level elites.

It's funny that you enjoy DL's boarding more -- many DL fliers dislike it because having "zone 1" be the third zone to board confuses infrequent fliers at the gate and leads to more crowding than might be the case if those people's boarding passes said "zone 5" or whatever the AA equivalent is, so that people were more likely to think "I guess I'm boarding pretty late, I'll stay seated for a bit." But some things are just always grass greener on the other side!

Also, btw, I think you also earn 7x miles per dollar spent if you're AA Gold (the same as DL Silver)? UA and AA both basically copied DL's miles-earned-per-dollar-spent structure.