I'm just a premed like you, so please take that into account when deciding how much weight to give this post.
My impression is that it's easy to overthink this, and that LORs are so univerally good, so it's difficult and rare to stand out from the crowd. That's the bad news. The good news is that I don't really think they move the needle for me people unless they suck. So, that's a pretty low bar -- get a letter that doesn't suck.
That said, only you know, from among all your candidates, who is most likely to write the most personal, well written letter about you. That's always who you should choose, without regard to who else likes them, what class it was, whether you were a TA, even whether you hit it off, etc. The only thing that matters is the quality of the letter they are likely to write. Some of those factors might be relevant, others not so much. For example, even if you didn't hit it off, a prof who is known for being supportive and writing great letters might produce the best letter you can get.