While we we eating lunch in the back of our car in the parking lot at the Park Avenue trailhead, a group of three and a guide arrived. We talked to the guide briefly, who said she was taking them to Tierdrop, but she had never done U-Turn. We relaxed at the car for a while to let them get a head start before we went back out for U-Turn. We saved U-Turn for last because it finished closest to the car. We caught up with them when we exited the gully to the slick rock plateau area, where the guide was going over instructions with the group. U-turn makes a sharp right at the top of the gully and traverses the ridge line to an easy but somewhat exposed slickrock scramble up a dome to the mouth of the canyon. The canyon starts with a low-grade slab that would be reasonable to downclimb if you were feeling up for the challenge, but we found a slung tree and chose to rappel. I wanted to rig the toggle to reduce rope pull across the slab, but I wasn't able to get a comfortable placement and switched to a biner block. After this slab, you landed on a bit of a shelf where skirting the left wall behind a large rocky formation, I found a pair of bolts. They looked awkward to get to as you squeezed behind the rock into a short downclimb, but it wasn't as bad as it looked. This rappel followed a short slab before dropping to a open sandy area. At the end of this sandy area, the canyon opens up through an opening where you re greeted with an amazing overlook far out into the park. Going through this opening brings you to a slick rock area. We followed a path of least resistance traversing LDC, where we found our next rappel off of a slung rock horn. This was another slabby rappel that brings you to a flatter area that then required a bit of hiking downhill through rocky and sandy terrain to get to the last large shelf of the canyon. From here you traverse left rather far before finding the last rappel which goes down a corner to the canyon floor. Here we found a piece of webbing slung off a tree about 30' from the edge. The webbing was a single strand that reached over the start of the first rappel, but it also had an alpine butterfly about 10' further up, presumably as a courtesy loop. I assumed by this setup that rope drag would be an issue if the anchor point wasn't over the edge. I first considered rigging a toggle off the same tree, but there were a lot of prickly plants guarding it, so I decided to rig it off the webbing from the shorter alpine butterfly loop. This ended up being the only rigging of the trip that made me a bit nervous. The toggle had oriented vertically in this setup, and although it appeared that it would be ok once the rope laid over the edge, it wasn't completely obvious. Given my questions about this setup, I probably should have had my wife go first with the safety carabiners installed, but I had been going first all day to get pictures. Really, I should have just fought the plants and rigged something more confidence inspiring directly off the tree. Regardless, I went first with the carabiners installed until I navigated the edge, where I was able to see that it was better than it looked at first, hovering almost 2' off the ground. This rappel proceeded down a water worn corner and was a bit awkward before dumping you in the desert floor. My wife followed and noted that rappel was her least enjoyable of the day. The walk back to the car was quick from the end of U-Turn. We got back to the car with just enough time that we could climb "The Pickle" tower near the park entrance (which I had not-so-secretly wanted to sneak in before leaving), but my wife wanted to relax and hike around a bit. We compromised and did exactly what she wanted -- Summary of the three canyons: We found Tierdrop and Not Tierdrop to be of very similar style and quality. Both had a mix of easier slabby rappels, awesome free hanging rappels, great scenery, and mild challenges. I found Tierdrop to be a bit more aesthetically pleasing (a "sea of slickrock"), but Not Tierdrop had slightly better technical challenges. They are both great, and I would rate them as basically the same. U-Turn we found slightly less good and a bit easier than the other two, but still quite enjoyable. The rappels aren't as exciting or varied, and the last one is awkward, but not in the "this is so cool" kind of way. The view of the park from the sandy area after the second rappel is probably the best view of the park between the three. I would still gladly do it again, but I'd prefer one of the other two.