My friend owns both 7th Gen. & 5th Gen. iPod Classic.
He said 5th Gen. iPod Classic has a better sound quality than 7th Gen. iPod Classic.
He also mentioned 5th Gen. iPod Classic sounds very much better than Fiio X3 especially with LO to external amp.
It is very interested to find out the sound quality comparison between DX50 vs. 5th Gen. iPod Classic. :)
Seems like the contendants in this price bracket would be the iBasso DX50, FiiO X3, iPod Classic 7th, iPod Classic 5th, HiFiMan HM603, and maybe the AK100, though it's way out of the price bracket. If only somebody had all these DAPs...