It seems some people might be construing reactions to tickling, e.g., body language, verbal, or even sounds they make that aren't exactly laughing, like a kind of squeaking or giggling, with laughter, but assuming we are talking about reactions to the tickling in general, I definitely agree about Louisa on UK Tickling and I also love UK Tickling's Tanya Atherton's reactions, like the way she tries to fight it before laughing.
If we're talking about purely laughter, I loved Shelly Dare aka Sunshine's laughter, but also her reactions were great too and really showed a lot of personality. Generally, I ultimately prefer submissive type lees. Most laughter is great, but the one type of laughter I can't stand is the loud screams, especially when that's basically the only reaction you get from them 😆