Very nice. Truth be told I'm kind of jonesing for a used Stello U3 which I could use with an XLR adapter to directly connect it to the M51 at the back. At £365 new it's too much though, so it'd have to be 2nd hand. The other option will be to see if the new JKenny converter is compatible with the SBT as it's USB Audio Class 2, but that's about £330 as well, although it won't need an AQVOX or some such, which I'd have to buy for the U3.
I had the same thoughts as first about the Stello U3 but the price keeped me away. One day I'll be happy to compare them both, but for now I love the sound of the hiface 2. I've ordered the 5VUSB power injector to try to improve it even more... in the meanwhile looks like Audiofanboy have a great time start on post #291.