People say, once you go gut, you never go back to steel. It's truth for me.
Pros - They are actually louder and project more than the heavy gauge steel strings I've used before. They are also capable of playing much softer than steel strings.
The colour range is huge.
They are very light under the left hand, thumb position doesn't hurt.
You don't have to change tailpiece, the knots fit right in finetuners, to be sure it doesn't cut in the knot I added small pieces of leather underneath it.
Cons - tuning - for first 3 days you only tune
They are very thick. A is thicker than steel G, D is thicker than C.
They feel very sticky to the fingers, probably fault of winding. It's hard to slide on them.