NW is not still in bankruptsy.
I switched from DL as a PM because I got pissed at SlyMiles changes AND no more segment credit. (I was 3MM, PM and FC for whatever that all means) This was 3-4 years ago.
Since then, I have been on only a handful of DL flights and am PE with NW.
I can't comment on west coast service.
In my opinion, both airlines are comparable. DL does offer IFE on some domestic flights, NW doesn't. This is of no interest to me because I bring an Ipod or DVD player to watch and listen to what I want, not what they think that I want.
My upgrade % as been much higher with NW. (Even my first year as GE)
Neither carrier is anything to write home about. Service on both is about as good, or bad, as the other.
I do like NW's hubs better than ATL. But that's just me. (ATL has made some changes and seems to be getting better)
Either line's club membership gets you into the other's, as well as CO. BTY, I am stld that CO is better than either DL or NW, but no personal knowledge of that.
Go with the company that gets you where you want to go. If segments are important, go with NW.