There isn't. The better gain (58 db vs 50) is really the only reason to get the Audient, and that's if cost doesn't really matter to you as it's far more expensive. Well unless the nice big volume knob is a big deal too.
In my quest to mic up my amp (with an SM57 and a good ribbon mic) I bought and returned:
- Scarlett (weak preamps, couldn't drive the SM57 worth shit)
- Steinberg UR44 (stronger preamp but not enough)
- Motu AVB mk4 (good preamp but killed the USB driver on my Mac laptop, every time -- no more mouse etc)
And wound up with an Audient id44. Strong preamp, and the DIs for guitar/bass are sweet. Enough inputs and output to do interesting routing.
Regarding the USB power surge issue with the Audient, I got a response from their support today:
On the iD14 there is over voltage protection on the USB input to protect against potential surges from USB ports.
Unfortunately on very rare occasions a unit may have problems, which you may see reported online, but this would account for a very small amount of iD14's. Furthermore, we provide a 12 months warranty with all our products for the very rare cases where something goes wrong.
The unit should be fine using either USB or the 12V power supply.
I am considering getting one of new 3rd Gen Scarletts to try something new. The specs look good and it appears that they have done something about lowering the latency. As I'm only going to hook up a two synths, USB DAW/midi, and no mics, they seem like pretty good value.