It's the worst case scenario: let's make a headphone that's really small and sealed (an acoustic nightmare), and that folds up for easy packing (a mechanical nightmare). What amazed us was how very good three of the four headphones sounded.
During the tests it was obvious pretty quickly that the Sennheiser HD 228 just wasn't cutting it. The sound was just 'okay' in the face of stellar competition, and the headphone earpieces simply rotate flat, which is handy for slipping them into a drawer or briefcase but doesn't really make them any smaller.
The Audio Technica ATH_FC700A and AKG K81DJ were roughly the same size both when open or folded into their compact transportation and storage mode. The FC700A was more lively sounding with a slight tendency toward being a bit bright; while the K81DJ was more punchy with thumpin' bass with a slight tendency to sound a bit muffled. The FC700A was a superior headphone for unamplified instruments, while the K81DJ hit the urban beat hard.
The Sennheiser PX 200-II was slightly superior to the two cans above but might not be quite as involving when one of the other cans was playing to its strengths. The slightly larger size of the other two cans might also make them a bit more comfortable for longer listening sessions, and the larger size earpads make for somewhat better isolation --- though if you really want isolation a full-size headphone would be a better choice. The really great thing about the Sennheiser PX 200-II is that they are a lot smaller when folded up than the other cans here ... a lot smaller. And you won't be giving up any sound quality to get this added convenience.
As you can see I had three victims for this test, and though I didn't write about it, the old Sennheiser PX 200 was in the mix.