I think the 2nd Tiers should be the Ivy League and vice versa, cause in this day and age nobody should be paying more than $400 for a DAP. If there are any 2nd tier players (in your list) that cost more, boot it out too.
I would say there are 2 leagues in DAPs, one is being the Ivy League.
- iBasso DX100 (aging reference best sounded DAP),
- iBasso HDP-R10 (face-lifted with longer batter,
- HiFiman HM-901 (the best sound or poor in build quality)
- iRiver AK1200 (the most expensive & elegant)
- Colofly C4 (againg & no firmware upate)
- Fiio X5 (soon, it is a black horse)
There other one I would call it as " 2nd Tiers"
- Fiio X3 (great sound & great price)
- iRiver AK100 (the best sound but most expensive)
- Hisound Nova 3
- HiFiman HM-60X series
- Colorfly C3+C&CBH (great sound but a lot of limitation)
- iBasso DX50 (soon, it is a black horse)