Yep, get an I2S DAC. No question. You’ll have less hassle in the long-run.
Haven’t heard the Wolfson, but I believe it has a lower output than the others, so if your amplifier is low powered and/or your speaks have low sensitivity, then you may not be able to get the volume you need - only 1 Vrms vs 2Vrms in some of the other I2S DACs. Just something to be aware of.
But anyway, luckily there are many I2S DACs to choose from:
I don’t think the lower output is a problem since my amp has plenty of power.
What about sound quality from the dacs in the list?
which one should i choose for best sound quality?
today i have a apple tv and airport express and i want the volumio to beat them in sound quality if it is possible.
That’s the million dollar question! It’s so subjective. All you can do is audition them. I reckon that’ll it’ll be hard to tell the difference.
Although it’s not such a silly idea. Many of the I2S DACs are cheap and easy to attach to the PI. Simply sell the ones you least like on Ebay. Maybe some of the developers would accept returns (as long as you pay return shipping).
I don’t think the Airport Express produces the best analogue output (http://www.stereophile.com/digitalprocessors/505apple/), so I’m sure any of the I2S DACs will better that. I’m sure they’ll be better than the Apple TV as well, because it’s a (cheapish) jack-of-all-trades device.