Funny how everyone experiences things differntely--I think the flat pads are the best for comfort but the absolute worst for sound. I hate what they do to the bass, the highs, the tonal character of the midrange and the transparency but I think they are comfortable as all heck compared to the modded senns or reversed/regular bowls.
Anyway most people love the sound of the flat pads so make sure to try them--along with all of the other pad combinations--no matter which Grados you own.