And that seems to be pretty common for me in these games--more often than not, my favorite LI isn't the one I'd consider best-looking.
I've been thinking about this a bit lately--it's easy enough to say, "I like this LI; that one, not so much," but sometimes harder to figure out why that is.
In the AVN context, it isn't generally looks. Sure, IRL, they're a factor, but in an AVN, everyone's at least an 8 (with the possible exception of Yona in A House in the Rift)--I'll like some looks better and others less, but just about all I've played are easily "good enough."
I said upthread that personality seems to be the big factor for me, but I think I'd amend that a bit to say it's the romantic relationship that does it (particularly when there's a friends-to-lovers component to it). I've been falling hard for Jenny in Ripples through the last two updates there, and a large part of that is that she's clearly so in love with that MC--her warm and caring personality just adds to the charm. Or Annie in Eternum--she and MC have been crushing on each other for the past 8 years and are finally acting on it. Or Lucy in Between Humanity--she's obviously been crushing on MC for some time; hard to tell if he has (though he now is), but he hasn't yet listened to me telling him, "just kiss her already!"
Here? Well, it's a bit harder, because we've set up that everyone is a girlfriend. Lucy is the most overtly loving, though, which I think has a lot to do with why she's my #1. Sarah's personality isn't Lucy's, but I think MC's mission to convince her that he's actually into her is rubbing off on me. And now that she's in the gang, so much the better.