DL is the obvious suggestion. It will be similar to flying UA ex-SAN in terms of connecting via another hub, except the club isn't quite as good as UA's. I've found lots to like with DL, as well as some areas where UA has advantages. You really have to try for yourself and decide what's most important to you.

The more I buy discount front cabin, the less important I find status. I'm also finding it very difficult to use GPUs and UA miles these days. RPUs have been worthless for a while already.