The W4S is in many ways comparable to the MDAC: if you add a better power section and async 24/192 USB, you have a similar machine. The extra cash buys you a little more finesse sonically, but both the W4S and Audiolab are dynamic Sabre designs.
By all means give me a bell in the morning if you want to check it out: like I said, the postage is on you, but I don't need any form of security other than a swipe of your credit or debit card. No charge for the loan: that's just the way we roll over here in fun-loving computer audio land.
We have demonstrator Metrum, Blacknote, Burson, W4S and Antelope DACs out for evaulation (don't ask for a go on the Rubicon yet), but you're welcome to borrow anything back at base that's not booked out this month. What are forums for?!