I can't pretend to know the best, but I have heard the Cary CD 303/300 with HDCDs and thought it was very appealing...it is also a very versatile player.
Cary's new player, the 306 Professional does HDCD and people seem to like it, but I haven't heard it. What's
I guess it boils down to what best means to you, vis-a-vis what you're missing from the Sonic Frontiers