Keep in mind there are 2 versions of the smilely face DSP-5500HC's as well. All DSP-5500HC's have smilely face but some are 7 Segment Displays (older) and Dot Matrix Displays.

As others stated any that is 24/96 will sound like the latest version of these sld today.

Anything cosmetically older should go for less money.

- Fiddler (IMHO)

If you think listening to music is fun, try learning an instrument.
HT: G61RSL, 4x5K, 5.5KHC, 2xSC6000, Transporter, HD621, Philips BDP7501 4K, Tivo, 65" LG OLED 4K C6
Computer: Foobar2000, 5K, Mojo, HiFiMan HE1000 V2