I would obviously support any of them wholeheartedly in the general. I am at the point where electability is EVERYTHING. I barely even care what their core issues are - ANY democrat is better than any republican at this point. So I judge candidates on their ability to defeat the republican candidate, which may or may not be Donald Trump.
Gillibrand strikes me as weak. What some see as a "bubbly personality" I see as a weakness. We are talking about electing the first female president here. For that to happen, said female candidate would probably have to exude strength. Or at the very least strong competence. Gillibrand fails on both counts as I see it. This is with the caveat that I am from Denmark and not exposed to regular senators, house members and governors the way that americans are, so I am basing this on watching a few interviews with her.
Klobuchar could be too boring for the primary, but might be a very solid general election candidate. She appears competent, quite likable and pretty much squeaky clean. She would probably be the hardest target for the usual GOP/FOx/Talk radio hit job that they'll do on any dem candidate. That is a very good thing.
Harris is the one I have seen the least of the three but what I have seen has been promising. She seems competent and well spoken and her mixed racial background could potentially boost her in the primaries.
Basically, I'd take Gillibrand last of those three. Undecided on whether I prefer Harris or Klobuchar at this point.
I don't think Gillibrand is weak but I'd probably agree that she exudes less strength or authority than the other two. I realise some of the comments may exhibit a double standard. We don't comment on how much male candidates smile or if their personalities are bubbly. However this isn't Europe. Americans (unfortunately) vote for personality more than depth of knowledge or smarts. As we saw in 2016... And women being strong might also be used against them.. Gillibrand probably comes across as the least threatening to a certain type of person.
Klobuchar is solid like you said but I just don't see her as someone who can excite the base. And I also don't know that we know she's is squeaky clean, given that she's a former prosecutor there's bound to be something that's gonna anger some interest group ( Harris was widely regarded as one of the most progressive AGs in the country but has caught heat for some of the things she did or in some cases didn't do.) Klobuchar just hasn't been vetted yet because there hasn't been as much hype around her as the other two.
My thinking was that Gillibrand is probably more ready for 2020. Harris is too green and it's harder to judge how effective she would be on the campaign trail given that she's new to this and we haven't seen that much. But after watching her on the beat with ari the other night I am not ruling her out for 2020. She came across as smart but also really personable and warm. It was a very good talk show debut.