How much does a DAC do the more expensive it is?

and then there's this, too: a central component like a new Technics integrated, say the su-r1000 if you have the cash, or an Accuphase with the dac module, and don't add more "stuff" to your chain.  The Marantz Ruby sacd player / dac unit also sports fine dacs, and thus does double duty, if your amp is analogue.

but, I know people on this forum have fun playing around with "separates" ... but dac diminishing returns is hard and real.  usually "better" is really just "different"... and even then the differences are usually subtle.  

swapping out dacs can lead one on an endless rabbit hole with no final bottom, but again I acknowledge that's technophile fun and fine as long as it doesn't detract from a musicphile goal of enjoyment of music (if one is actually a musicphile, and if not well then have at the tech chase and enjoy the trip).  

@audiom3 +1

"I suspect they'll sound closer to one another than their cost difference suggests." 

Cost is only one of many indicators of how good something is.

Having said that, like many things in life unless someone is totally screwing you typically get what you pay for.

If you can't tell the difference between a $200 or $2,000 or $20,000 DAC then you've either been blessed with poor hearing and won't suffer from upgradeitis or you need to work on the rest of your system so that you can realize what a difference a great source can make.

@big_greg : Spot on!

It do a lot more