Their service to SEA is terrible. Competition here would be nice to CA/AZ but Delta is very reliable and inexpensive (plus it flies the superior Airbus equipment) to Phoenix, so that's a tough route to win.
Delta flies pretty much everything including the 737.
Depends on the route. The last time I flew Alaska to SEA was on a 737-400 a couple years ago. They've since been retired, but their current interiors are rather sterile and have those awful slimline seats. Meanwhile I think Delta will be bringing the A220 to Seattle.
Delta also flies a lot of regional carriers to SEA (and both Compass and SkyWest are pretty mediocre out of SEA). I'll take the 2x2 seating of a CRJ/ERJ over a 737 (or the Dash-8s) any day, especially Delta's newer low density layout. The Dash 8 isn't bad for a turboprop, but it's still a turboprop.
I agree - meant to say that most of the SEA-PHX legs have been route changed to Airbus lately, which has been nice.
If you think they're nice, you should've seen them with the Virgin America interior.
As someone flying out of the Bay Area, Alaska just isn't that compelling. Their route network is smaller than the big 3 and their product isn't well differentiated from the rest. I've heard good things about their customer service, but so far Delta has done right by me when either I or they have screwed up.
Delta flies pretty much everything including the 737.