I've used IWB exclusively since I started carrying, I started with a Cross Breed and later bought a Comp Tac MTAC in the sake of experimenting.
The Supertuck is more comfortable in general, I have found though that the width of it causes one side of my pants to sag a bit (in spite of the kydex Minotaur gun belt I wear). It does squeak a bit as others have mentioned though and it is well broken in. This may be something that some saddle soap(?) would help alleviate.
The comp tach is slightly less comfortable (not uncomfortable), but I prefer it to the Super tuck. It's easier to pop on, I like the retention a little better, it doesn't load one side of my pants as much for some reason. It also holds the gun slightly differently and is a touch less visible on close examination.
If I'm going to be on my feet, I wear the Comp Tach, driving/ sitting down more, the super tuck.
Both, of course, have clip options based on your intended use, crossbreed even makes them in different colors to match your shoes I guess
Both are "tuck-able", imho neither is any better at this requirement than the other, although as mentioned I find the comp tach is a touch less visible under scrutiny both in shirt and under tucked in shirt.