Absolutely underwhelming and disappointing - if you don't count the big waterfall in the very end of it (which isn't really anything that astonishing if you have seen a fair share of other before), there isn't much to see in the Lichtensteinklamm. Others like Sigmund-Thun-Klamm or Seisenbergklamm have much more to offer and have left significantly greater impression on me.

If anything the entire place is one big overwhelming tourist attraction with a ton of souvenir shops and restaurants on every corner and an awful amount of people everywhere (four parking lots, which are constantly full say a lot about that).

I was there around 10AM and it was already crowded, when we were leaving in the early afternoon people were standing long lines for tickets and I frankly can't imagine how much of an unpleasant experience it had to be for them once they finally got in because the biggest mistake this place has is that there is only one narrow route in the entire Klamm - you are passing by people who are leaving and even those who have just entered, constantly standing in the lines, waiting for people to pass or you abruptly have to stop because someone in front of you suddenly decided that they want to take photo or take a break because they were out of breath from all the stairs that were everywhere... There wasn't really any way how to truly enjoy and appreciate the little beauty this place has.