In case anybody is wondering whether or not the speed difference matters in practical applications, here is my recent experience.
 
I received a Toshiba 3T SATA/6G drive yesterday to go into a new USB2/3 dock.  This is for backups.
 
I plugged it in and started a backup+verify with Reflect.  The total size of the backup = 802G.  AFTER starting I noticed I had it plugged into a USB2 port instead of a USB3 port.  I let it run to see what the results would be.  The total time for the backup & verify ended up being 20:53:21, with an overall transfer rate of 153Mb/s reported by Reflect.
 
I reconnected to a USB3 port and ran another backup+verify of 200G.  This took 1:13:56, with an overall transfer rate of 456Mb/s.
 
After doing some quick math I'm sold on USB3 for backups 

True dat!!
 
USB3 is the bomb!! (without doing any math) 

3.1 is suppose to be twice as fast as 3.0

Now that Intel has added Thunderbolt 3 support at the chip level, and some devices are shipping with it (like an Alienware laptop I looked at recently), I'm looking forward to getting my audio i/f as far from the USB hub mess as possible (I have 6 USB2 ports and 4 USB3 ports, some front, some back; no Dell documentation on internal, physical connections (what's a real hub vs a virtual hub)).
 
But you're right about USB3. I installed NI K9U off of an external USB hard drive via USB3. I don't have numbers, but the install went much more quickly than I expected.

myconsumerclub
3.1 is suppose to be twice as fast as 3.0

 
And it's less filling!!!
 
(sorry-I don't know what comes over me sometimes)

I don't remember where I found out about it, but the MS USBView utility is really helpful for getting a handle on all things USB.
 

 

Nice looking tool! Did some looking around and found this spin-off based on the MS code in GitHub. It is constantly updated (the web page says v2.5.8; there was a 29 Nov update to v2.5.9 that is downloadable). It comes in 32- and 64-bit versions, and works better in Win10 than the old MS USBView.exe (my USB3 ports report correctly).

 
http://www.uwe-sieber.de/usbtreeview_e.html

so why aren't usb audio interfaces geared for usb3?
 

Some are starting to show up.  For example, the Tascam 20x20 is a USB3 interface

There are a few though none come to mind at the moment, other than the new PreSonus Studio 192 and I'm sure I've read about something else that is usb3. I think the Tascam 20X20 is.
Michael