Digital Formats

Wondering if there are any real differences in digital players. For instance I currently run a wadia 170I into a Theta dac. Would there be any real sonic differences in going to a high Rez music player such as the Sony HAP-Z1ES or any of the other music servers currently out?
"If my music is ripped in wav and apple lossless then I would get no benefit in going from my current set up of a wadia I70I into my Theta Dac to the Sony HAP Z1?"

You would need to listen to both setup's and pick the one that sounds best.
There in lies the issue would have to buy the Sony to compare and if no noticeable gain in sound would be stuck to unload the unit..
The way I see it HiRez music is another way for the audio industry to sell more gear and music. If redbook is presented properly there is no need to go to hirez formats. All of the gear in the chain matters from the transport-dac-preamp-amp-speaker!
At one time I had a custom Audio Note Kits set up. The guy who built the "kits" for me went all out with Blackgate caps, 2w tantalum resistors, Audio Note transformers in the 300b amp, silver hook up wire, and so much more. I had a 47 Labs Flatfish transport that was highly modified with a superclock, BG caps, and a custom battery power supply. The speakers were Lowther Medallion 2 BLH horns.
The amount of detail, tone, 3D imaging and sound staging was phenomenal!
I had this set up for about 3 years until the economy went down, and I sold off all except the 47 Labs Flatfish transport. To this day I still regret selling the dac (ANK 2.1b Signature), but hey that's life.

I have used the FF with a variety of dacs since (some mine, some borrowed from friends). Each time the redbook has out performed or equaled HiRez DSD tracks on the same dac. I have lent it to friends and they verify this to.

To achieve this the cost can be kinda high. A new unmodded Flatfish transport is 5k. I have about $6k ($4k new)into mine and keep getting offers from "friends", but they are way to low for consideration.

Point is you can jump on the HiRez train and pay a lot more for the same music you already have, or put that money into the purchase of exceptional gear. Enjoy the music you own and purchase new music for way less than HiRez.

Just my 2c

"11-29-15: 2channeljunkie
There in lies the issue would have to buy the Sony to compare and if no noticeable gain in sound would be stuck to unload the unit.."

That's the nature of the hobby. You listen and compare. To be honest, unless you have issues with your current setup, I don't see the Sony as an upgrade.
Unless the music you want was recorded and processed as hi-res, then I don't see why there would be much advantage in paying more $$ for upsampled redbook quality files. That's not based on any listening tests, but if the information isn't there in the first place, I'm not sure there is any way to reliably predict whether some kind of an algorithm that interpolates what those additional "bits" would sound "better". Take this w a grain of salt, tho, 'cause I have no real understanding of the way these digital products actually work.