Title says it all, Im talking about interface-computer connection. One guy said that always get an interface with 2.0 USB connection. But hows that really different with 1.1?
2.0 is a faster connection, I'm not sure exactly how it relates to interfaces but I'd imagine you would be able to record more separate instrument/mic inputs at once with better quality through 2.0 than 1.1.
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2.0 is reverse compatible with 1.1.

The only major difference is speed the 2.0 has a raw data rate of 480 mb/sec as opposed to the 1.1 12 mb/sec.

Now for recording purposes the extra speed doesn't really matter, since most audio quality bit rates are far below even the lower number, you won't be slowed down due to the slower connection. It's more important for video editing, file transfers and most importantly as a marketting tool to keep up with firewire.
"USB 1.1 allowed a maximum transfer rate of 12Mbits/second. USB mice and keyboards need only 1.5Mbits/s to function. That performance level is also named 'USB'.

USB 2.0 has a raw data rate at 480Mbps, and it is rated 40 times faster than its predecessor interface, USB 1.1, which tops at 12Mbps. Originally, USB 2.0 was intended to go only as fast as 240Mbps, but then, USB 2.0 Promoter Group increased the speed to 480Mbps in October 1999."

Taken directly from a random site I found...
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Actually regarding interfaces and audio in general there is a MAJOR difference between the two: USB 1.1 is generally limited to 2 in 2 out 48kHz/16-bit or 2 out 0 in 96kHz/24-bit. Always limited to stereo (ins and outs). USB 2 is able to do multichannel and different sampling rates/bit depth. I think that's a huge difference in regards to audio.
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