I looked at all of them, held off, and then eventually decided that I really didn't want storage.
First of all, I keep stuff under the driver's side rear seat and it all stays in place without a special storage device. Secondly, I frequently go camping and trips up north where I toss lots of gear/bags into the back. I love flipping up the rear seats and having lots of space. Lastly, I finally added my old subwoofer to this truck since I've got the base (non-Alpine/non-HK) system. I just built a custom box and put it under the rear passenger seat (it is easily removable) but a seat storage bin would have been in the way.
I'm just giving you my two cents to consider.