Personally I don't think the 175 will go too senior in SFO, most ppl aren't going to it because they are close to upgrade and or leaving and don't want a training Event. The bro ppl will of course be forced
To go somewhere and I would think the CRJ is the better choice, many more trips on the CRJ and the option to pick up stuff in lax. 175 so far has contracted to be 40 planes between what will be three bases (unless Den doesn't open which is a rumor due to a/c performance) it won't have that many trips out of SFO. Delta benefits are a big deal (right now 175 PPl can't even jumpseat on delta) because to go international business is a lot cheaper, if that doesn't matter to you and you don't commute on delta then it's not a big deal.