Woo AW22 1st Gen or 2nd Gen - Do they sound the same? Same build quality?

Hello,
I have an opportunity to buy a Woo WA22 1st generation and would like to know the differences between it and the 2nd generation. I know that the 2nd Gen has an XLR output for a power amp/speakers- Is this the only difference? 
But, does the 1st gen. sound as good? Other than the XLR outputs, is the quality of circuitry different or better on the 2nd generation?
In the WA22 1st Gen, I understand that the toggle switch enables the switch between RCA/XLR inputs. Does this mean that when it bis toggled to RCA Input, then an 'XLR to RCA' cable can be used to connect to a tube power amp to drive speakers? Would this degrade the sound in any way?
Any comments would be most welcome.