UDAP works fine. I have used one many times on float trips in Alaska. The entire thing weighs a couple pounds. Once you get the knack of it setting up camp becomes a rhythm and the fence only takes a few minutes. Just gives you some peace of mind + on the few times a trip we maintain a camp for more than 1 night we can go fish away from camp without worrying about the camp getting ransacked. I have had bears come through camp a half dozen times. One time a mama bear and her cubs tracks were around the fence, but they did not come in. I am a little embarrassed to use them, but like them! lol.
The UDAP runs on 2 D batteries. At least mine does. The fence is just a battery pack, wire and some carbon poles. It is extremely compact and lightweight. I haven't weighed mine, but it is for sure under 5lbs all in and in a tiny package. If I was hiking I would probably just practice good sense and if it was heavy bear country use a bear proof container. For a float trip where there is a heavy bear population the fence is ideal. You could easily hike with it too though. To each his own. If it makes the group comfortable, why not? In the Cascades I just hang my food and call it good. I have seen many black bears and 1 Grizz. Never had one come in a camp in hundreds of trips in the Cascades.
Snarlac, the photo is a long river in Bristol Bay. I know not everyone uses a fence. We like to cook fish right in camp and also hike the smaller tributaries after being camped. All our food is in bags in camp. Heck - there isn't even always a place to hang food, or put it away from camp without a hassle. Since we are on a river in prime fish season there are obviously lots of bears. Just eases the mind. That's all. I don't know if we would have ever have had an issue without the fence - I do know we haven't had one with it; and have had tracks close to it. I don't even know how many issues have been associated with the bears in that area. Yeah - there are a lot of bears, but they are wild - so are skittish and run away usually. Although we have had some odd Grizz behavior a few times that puts you on edge.