I agree with Elizabeth that an actually listening test of the component connected to your personal hifi is optimal however, you still might be able to tell a lot by listening to it at the store.
What I cannot understand are the price tags on current DAC's given that they're all over the place. I'm still happy with my Ayre QB 9 DSD DAC (with tweaks) even though it's antiquated and it retailed for $3,500.00 new. A reference DAC in today's market, from what I can tell, could retail for as high as $20,000.00 or as low as $1,500.00.The question being, will the high priced DAC produce a better analogue sound than the low priced DAC?