ITF tuls aren't practiced in my school but...
for about half year we started to teach Moon Moo tul for all persons with 3 kup and above who want to start in TKD patterns in tournaments. And... in november on international PUT tournament we had one silver and one gold medal in 2 kup and above division. We practice TSD.
Interesting choice... in our sequence, I am just learning Moon-Mu as a IV Dan, as one of my required patterns for V Dan. Not that there's anything in Moon-Mu that most 3rd gup and up don't know, just that, as you say, it's very technically difficult.
I know Chang Hon patterns from Chon-Ji to Ge-Baek and Moon-Moo
My favourite is Moon Moo becouse is the prettiest of all tuls and is very technical difficult.
Funny... that whole technical part is why I
don't pick Moon-Mu as my favorite! Actually, I do like it - I'm just not nearly as good at it as I want and need to be.
My least favourite is Joon-Gun.
Hmm... I'll admit that Joon-Gun isn't my favorite either, but I don't know that I'd say it was my least favorite; but then, I'm not sure what my least favorite is, either!
My favorite gup pattern is Won-Hyo - not for anything about the pattern, specifically, but because when I tested for my 5th gup high green belt (which required Won-Hyo), that was the first time I really felt like I had performed at the high end of the standard for my rank. My favorite black belt pattern is probably Po-Eun - like Moon-Mu, it is very technical, and most people don't do it right, but it's not nearly as physically demanding as Moon-Mu, and, when done right, can be a lot of fun.