If you are going to choose a high impedance headphone (example: Sennheiser HD 600) you will need an amp that can power that higher load with a large voltage swing. Some headphone amps can power lots of headphones great but sound terrible with high impedance loads.
For 300 or 600 ohm headphones you will usually find a tube based amp as the best solution. These amps are not great choices for many low impedance headphones because many low impedance headphones require larger current demands. A Bottlehead Crack is a great choice for Sennheiser HD 600 headphones but sounds lousy with Audeze LCD-X cans.
If you concentrate on Schiit headphone amps (a great choice for reasonably priced American made headphone amps) you will find that the Valhalla 2 is a great match for the Sennheiser HD-600.
As an alternative choice, the HiFi Man HE-400S, is a headphone that some reviewers prefer to the Sennheiser HD-600. For that headphone the Lyr 2 is a great choice that can drive almost any headphone made.
The Lyr 2 is a hybrid tube/Mosfet amp that has 6 Watts per channel at 32 ohms which is very high power. That sounds like an amp that could handle anything but the Valhalla 2 is a better choice for high impedance headphones.
You have to first choose the headphone you will use and then check its impedance. If the impedance is 300 ohms or higher, you will need a headphone amp like the Schiit Valhalla 2. If its a lower impedance headphone you will need an amp that has high power like the Lyr 2.
Good luck with your choice,
Ed
We don't shush around here!
Life is analog...digital is just samples thereof
