I have the SR80 and my friend has the MS-1. We had a listening session to compare the two, mostly with high quality MP3s from a laptop, or average quality mp3s from an ipod, both amped and unamped.
The SR80s were more aggressive, with stronger bass, but maybe less controlled. The mids and highs were more forward as well, with the upper register occasionally shrill.
The MS-1s were slightly more relaxed, the lows not as strong, and the highs not as piercing. More laid back in general.
For some music, the SR80s were more exciting. For other music, the MS-1's smoother presentation was an advantage.
Bottom line, it's up to you.
Both were just fine straight out of a laptop or ipod. Both benefited from an amp. But I've stopped taking my sr80's out of the house, unless I go on a really long trip. On the go, I need to use them at such a high volume since they're so open that it takes a lot to drown out the outside noise.
I was worried for my ears, so I got the JVC marshmallows and kramer modded them. I've been very happy with them so far.
I ordered a few more portable 'phones as well. I think if you want portable, you really should get closed phones or IEMs.