Backpack one was just released by Walmart/Ozark earlier this week and mine arrived last night. Basically same construction as the Jumbo Tote but in a smaller form factor and with straps to make it a backpack. Although no formal testing of it yet, looks to be a winner in my book (esp at $39).
The zipper looked different in photos. I'm wondering if it might be more watertight. Mine is supposed to arrive for pickup by Monday.
So, I've seen quite a few reviews of the larger Premium Jumbo Tote, but nobody seems to have used/reviewed the backpack version (the 20-can Ozark Trail Premium Backpack Cooler). I went ahead and ordered one to try. I'll do a quick review when I get it and have a chance to use it.
I didn't get a chance to do a controlled test, but I did take the backpack cooler on a camping trip last weekend. I wouldn't use it again for camping. It just doesn't hold enough. I had 1/2 gallon of milk, ~6 cans of soda, a liter container with some vodka, a small pack of potato salad, and a couple packs of hot dogs and that was all she could fit. Everything was prechilled and I filled the voids with ice cubes from my freezer (probably ~5lbs) and one blue ice pack to cover the top. We left Friday afternoon and temps were in the mid-90's. Overnight lows in the 60's. Back into the 90's Saturday. I had to re-ice (about 10lbs) Saturday around lunchtime. Everything stayed cold enough, but there was substantial melting each day. By Sunday, most of the ice had melted again. Unfortunately, the top zipper is not watertight. The backpack is very stable though, so tipping won't happen in most instances. You will want to pour out water before putting on your back though. Nobody wants a flood of ice-water on their back if they bend over.
Overall, I think the best use for the OT Premium Backpack cooler is a day at the beach, a picnic hike or, a day/night at a festival/concert. It probably won't hold much more than a 12-pack of cans with the appropriate amount of ice.
I also bought the 36-can Jumbo soft tote and it is substantially larger. Also, the Jumbo tote has noticeably more insulation on the top cover. Both are a good buy. The quality is quite good on both. The zippers are tough. The straps/padding on both are good quality. They are a nice addition to the collection.