I guess so...it sounds like I'd be a bit torn as well...thanks!
I think I prefer the signature of the HD650 as it engages me more with the music, makes my head bob and toes tap without being fatiguing. The soundstage is a bit larger with the HD650 but vocals seem closer to me.
The overall quality would go to the HE-500, it sounds more refined with better instrument separation and a bit deeper bass extension. The HE-500 sounds more neutral to my ears and as a result is less engaging in it's presentation. There is some high frequency with the HE-500 on certain songs that bother me also, with the HD650 it doesn't bother me. Vocals sound like they are a bit further back on the HE-500, like the person is singing across the room from me.
I really thought there would be a much larger difference between these cans but I guess this is where diminishing returns start kicking in.