Oppo's HA-1 is a very flexible headphone amp and home theatre DAC/pre-amp and about spot-on for the money.
Pros: No lack of inputs, including Bluetooth; Headphone amp is good all-round with plenty of power; Functionality is well thought-out.
Cons: Mute function for the pre-amp output only accessible on the remote. Knob feel for the volume is terrible. Display text is hard to read at a distance.