I like the fact that these devices aren't all exactly the same. Knowing the pros and cons of each is a big plus. And that is what this forum is all about, IMO.
I like my Air Stash and will continue to use it. It is light and easy to charge. No special cabling is required. I went on travel this past weekend and forgot my little box that holds my SD cards....so when I got ready to watch something, I had the wrong card inside. Fortunately, I had managed to grab the portable hard drive so I was able to use my laptop to move files around. So, here is a case where all those SD cards can be a bit problematic. Also, the one SD card I did have with me is slow as molasses. I need to deal with that, too.
I could also have used my personal cloud - the Pogo Plug Series 4 - which has two usb 3.0 ports, a SATA interface for a 2.5inch drive, and a couple of usb 2.0 ports. I currently have a 1 TB 3.5-inch drive plugged in. I can stream movies over this from anywhere, but you need decent internet speeds for make this doable, which I didn't have at my dad's house. But I could have downloaded a movie to my laptop or iPad, if I wanted to. I can also play mp3s over the web this way, as well as move files. BTW, I see no reason to connect usb 3.0 devices to this because the speed is of no benefit when streaming. So the slower usb 2.0 stuff work best. The sata interface means you can plug a 2.5-inch mechancial HD right in. Or you can use a flash drive or a larger HD like I'm doing now.
I also am thinking of getting a iUSBport, too (yeah, I' m a nutty gadget freak with no kids).
I got a Gauntlet Node yesterday and have put a 2.5 inch SSD inside (for now) to see how I like it. One disadvantage I see for it in that you need special plugs and cables to use it. Charging it up requires a barrel style connector, so you need a special cable when traveling. Also, while it has usb 3.0 which is nice (for large files the transfer speed is great), it still requires a special cable for that, too. And while it fits in a pocket, it is still far larger than the AirStash and I suspect, the iUSBport as well. The one advantage it has over Air Stash is larger capacity drives....right now I have a 512 GB SSD inside it!
I'll probably replace that with something else later (if I keep this)...but for now this is what I'm using to test it. It will take 2.5 inch SSD or HDs (laptop drives or portable HDs). I have lots of portable HDs sitting around, so I will probably rip one open to get to the HD inside. Again, if I keep this.