A few questions.
1. Do you have a particularly large library that you want to take with you on the go? (YES - Pioneer or Onkyo for their two TF Card slots.)
2a. Do you plan on utilizing wifi streaming services? (NO - Astell&Kern)
2b. If so, do you plan on using more than Tidal, Groove+ or Moov? (YES - Pioneer or Onkyo)
2c. If not, do you plan on utilizing offline storage for those services? (YES - Pioneer or Onkyo)
3. Do you need a 2.5mm balanced output? (YES - Anything but Onkyo DP-X1)
4. Do you prefer a more neutral or a more warm sound? (Neutral - Astell&Kern; Warm - Pioneer or Onkyo)
5. Do you use high impedance headphones? (Get an amp)
6. MQA? (YES - Pioneer or Onkyo)
7. Do you have a need to feel like you own the best? (Astell&Kern)
8. Budget?
Budget notwithstanding, my choice would be the Onkyo DP-X1A. I had the DP-X1 when it first came out and enjoyed it, but it seemed a bit warm sounding, particularly when I got ahold of the KANN. In terms of utility, you get Android 5.1.1 on the Onkyo and Pioneer which allows for the saving of Tidal offline (the reason I gave up the KANN, that and the fact I don't need all that power for my IEMs) and has better access to public wifi points or anywhere that requires a login or terms and conditions acceptance (such as where I do 2/3 of my listening). I strongly prefer the sound of the Astell&Kern range. If you are ok with a less than ideal user interface, for around the same cost as the Astell&Kern 70 MkII is the FiiO X7 MkII, which is my go-to player right now, but it isn't perfect.
You've narrowed it down to some good choices. Figure out what your use case will be and then go from there. If I had a music library I could fit onto a single TF card, the Astell & Kern range, particularly the AK 70 MkII would be one of my top 3 choices. Good luck and I'm sure you'll be happy when you plug in for the first time. Cheers!