no idea on unity but assuming it will be same or lesser that 272...
it is ok if you have easy drive headphones....
but event a modest amp or mojo eats them alive as an amp!
So depending on what headphones you have and how much you want to invest on it they are many but many good options.
Creek, arcam have very good headphone amps, arcam one is new but creek obh21a can be find used in Uk to a modest price and it is far better then 272 headphone amp let alone unity. Only V-1 is slightly better than OK with a price tag, headline is good but the power sources makes it very but very expensive.
Naim need push on its headphone game for sure....
Mojo/hugo/dave ( i listened only mojo/hugo) are very good headphone amps as well ( or what they say about Dave ) for price points.
