Ha good question Sir! Answer no I haven't, oops. BUT I did have a range of CDPs before and I am convinced 100% I am beyond that now. I have been active over at head-fi on the Rednet thread and many of those guys have been on the built up PC trail, modded server DIY and then Rednet Ethernet and LPS tweaks.
I have worked on Macs for years, so prefer to have complete control over the computer side. I can see a pre-built is a nice idea, not saying they don't sound better either. my journey was running Audirvana+ as the player software, then updating and tweaking the Laptop, then an iMac, then a Mac Mini and running it headless on screen share. I have the PS in it deactivated and running from a 12V LPS using the UpTone Audio MMC card kit. Then added the Rednet 3 which used Dante and I send Ethernet on 1000BaseT to the Rednet, then SPDIF out to my DAC. I also changed the power supply in the Rednet to LPS inside the chassis, so nice and neat.
TBH the dropping of USB was a huge upgrade. Then adding the LPS to the Mac Mini and then the Rednet 3. I am very happy right now. It is a dead simple end to end network, no switches or routers. I have my music files on an External Firewire drive (also on LPS). The whole system inc my DAC and amp is on a PS Audio P10 which also cleaned up things.
My aims may be different to some, as I am on no filter no up sampling DACs so never wanted to upsample on a server, which may be a other drive to spend on pre-built options? Also IMO even top servers still seem to have the PS in the one box, as it is socially more acceptable, easier to sell to more folk.
IMO digital sound is super sensitive to noise, any noise in the power lines or data. Getting rid of that noise gets you down to super smooth liquid sound, like vinyl. Ha Ha, all this crazy stuff to catch up to records that we had in the 80's - bonkers!!
But yes, there may be better servers out there, but I am not wanting to spend 10K on one, or be in a closed system. Computers date faster than anything I can think of, and 10K on a computer is insane to me. Maybe the TotalDAC servers are better value?