For context, I have been to the event 3 times. 2010, 2012, and my last being that of 2019. So I have a good amount of mazes. I will keep it relegated to Top 10, and explain the main 5.
1/2.) La Llorona (2012) & Us (2019)
3.) Alice Cooper Goes to Hell (2012)
4.) Texas Chainsaw Massacre (2012)
5.) The Curse of Pandora's Box (2019)
6.) Creepshow (2019)
7.) House of 1,000 Corpses (2010)
8.) The Walking Dead (2012)
9.) Holidayz in Hell (2019)
10.) Friday the 13th - Kill Jason Kill
It's a varied list, and small for the reason that I haven't been to the event as much as I would want (And while I want to include houses recorded in video, I feel that discounts my take on the matter. So, it's by in-person experiences. And for the most part, the Top 5 are incredibly interchangable at any given point, especially the top two.
La Llorona/Us = There's a very, very, very thin line in the sand between these two. So much so that these mazes jump from being the best constantly to me. For a complete experience, that is terrifying and jaw dropping, Us and La Llorona are at the top, because of just how much of a complete experience these two mazes *feel* IMO. Keep in mind, I was 13 when I went in La Llorona, but it was the maze that I wanted to go back into.
TCM 2012 = This was terrifying as hell. The venue for this maze was perfect for Leatherface, and the content and how they accurately depicted TCM 1973 scared the bejessus out of me. It's a nostalgia and bias choice, but I have to put it here.
Alice Cooper Goes to Hell = I love House of 1,000 Corpses. But Goes to Hell is a extremely better 3D maze, that's scale and tones match incredibly well. I really wish we got a continuation of Cooper's partnership, because I would've loved to see what else that could've done with his iconography. The way they translated the music and the scares is outstanding and I cannot get enough of it.
The Curse of Pandora's Box = Simplicity sometimes to me, equals quality. Pandora's Box, while reusing assets I've seen from videos, feels really good, when experienced in full. The Preshow element of Pandora's Box is an absolute highlight to me, as is how they scared the living hell out of me. Years after TCM, I think this maze shines as something that I wish Horror Nights strikes with (while using the quality from Us to consideration) of how they use a scare.