Best DAC for under $500


I'm looking for a DAC with good transparency and dynamics. Is there a DAC with good bang for the buck in this price range that would offer a substantial improvement over a $1,000 CDP?
I've considered EAD DSP 7000 MK III and Audio Alchemy DDI pro but concerned about repairs.
So two other options are dAck $399 and the CI Audio VDA-1 $349
cdc
I personally really love my Nixon DAC which sells for $250 new. However, it is a bit cosmetically challenged. But, it is super small, so you can hide it. I am not at all familiar with your transport. However, from what I gathered from various posts on AA and AC, the Dack! does a phenomenol job but performs better in systems that are on the euphoric side. Whereas, the Nixon does better in more neutral systems.

I used to have the 563, and I don't think that DAC can touch either the Nixon and Dack. I used to have the CI DAC too with the VAC upgrade. That was a pretty good DAC, but I personally prefer the sonic characteristic of the Nixon better perhaps because it lacks digital filters. However, if you don't like laid back sounding DACs, perhaps the CI is better for you.
used Perpetual P-3A for ~$450 !
Check the stereophile review http://www.stereophile.com/printarchives.cgi?455
you'll know why.