I snagged a C2500 just after the C2600 was introduced. I believe the main performance difference is the C2600 has a newer, and "better" ESS DAC chipset and it has the new headphone amplifier built in.
As I don't use the built in DAC and hardly ever listen to headphones, the C2500 seemed like a better choice for me.
As I don't use the built in DAC and hardly ever listen to headphones, the C2500 seemed like a better choice for me.