I too am a fan of those sights because of how compact and effective they are. They are not user friendly to adjust, but once you get then set for a gun's pet load they are rock solid.
Don't need any at present, but I spent a lot of time finding one two years ago and know how hard they are to find these days. If I didn't already have peeps on my two TC Hawkens I'd be quite happy to pay $60 for one.