Have both. The Q might be a bit more neutral as in frequency response. That's fine but it's not bumpy in the mid-bass which makes it less "fun". The 325is are brighter up top, not too much for me, but with a much more pleasing mid-range. The Q is a little plastiky in the mids, not quite real. The Grados have that mid-bass hump which I don't mind at all. I've instantly switched back and forth and I'll take the Grados every time. I really wanted to like the Q701 (I do) and as long as you don't do instant comparos, you'll be O.K.. Please spare me that the best headphones have to be "neutral". It ain't so, but, YMMV.
I know this thread is old, but I'm trying to decide whether or not I need to get my Grado 325i's back (broke them) or get a good IEM (Westone 4). I do have the Q701's and they have been pretty great for music. Your post reminds me of why I fell in love w/ them. In fact, I have a pic of me "listening" to them here:
The Q701's make me smile all stupid like w/ their soundstage, the 880's made me smile w/ their detail retrieval, but ONLY the Grados forced me onto my feet and rock out for a picture so fellow head-fi'ers could see the "Grado Effect."