Can you get a K701 for $250?
Do you need isolation?
What kind of sound are you looking for?... bass heavy or bright? In your head sounding or very spatious and distant?
Are you the kind of music listener who is always picking apart notes and sounds in your head, straining for every last musical detail and nuance?... or are you just tapping your feet and grooving to the music?
I'm bored, so here are some of my general comments:
MS1, warm, balanced, easily the most tame SR series Grado, easiest to like. Doesn't quite have the sub-bass extension of some of the other cans on this list. Sounds best with bowl pads and a tube amp. Second cheapest can on this list. Nice all - rounder, no major strengths or flaws. My biggest complaint: Comfy pads make it sound conjested.
HD580, mushy, distant, nice spatial separation but center stage is a little vacant. NEEDS robust amplification, under-amped sounds like fart. Recession from 3500-5500 Hz makes guitars sound mushy and devoid of dynamics. My biggest complaint: upper midrange recession, gets boring after a while.
DT770, closed, bassy. Nice forward upper mids. Good soundstage for a closed can. Recession from 550-900 Hz makes guitars sound thin. Sound reminds me a lot of a mid-fi 5.1 home theater. My biggest complaint: Lower midrange recession, just isn't quite balanced enough for my tastes.
K240s, bass heavy, muddy at times, needs robust amplification. very comfey, although pleather earpads get very sweaty. Cheapest can on tihs list. My biggest complaint: Muddy signature makes it a little hard to pick out details.
SR225, Take the MS1, and boost upper mids and kick drum. Comes with bowl pads. Sounds best with tube amplification. My biggest complaint: Just a a little pricey IMHO. New they sell for a little over $200. Ive seen used MS2s sell for $250.
K501, spatious, nice detail resolution, No bass. More than any other phone on this list, needs amplification.... warm bassy amplification. My biggest complaint: no bass = no fun.
MS2, DING DING DING!!! Winner!!! Used the MS2i model sells for $250. MS2 is about $50 less, used. Easy to drive. Nice sub-bass and treble extension. Can be a little bright, but thats a matter of taste, and nothing some warm amplification can't solve. The most detail revealing can on this list. Nice spatial image, not as "in your head" sounding as the SR225, yet not as distant sounding as the HD580/K240s.
You might also want to consider the SR325i, used. Ive never heard one though.
biggest piece of advice I can offer is to get out and listen to them. Let YOUR ears guide you. What sounds good IS good.
Phwew!!