I would agree with most of your impressions, the difference is, that I prefer the Q701 .
Although I find the HD650 harder to drive, at least, that is my experience.
On another note, just yesterday I plugged my Q701 in the motherboard soundcard headphone jack, because I didn't want to turn on the DAC and amp for 15 minutes of use. I don't remember ever doing that. So, what I found out is that the Q701 were much brighter then on my original setup and in that regard I would understand, if somebody would think they can be a bit harsh on the highs. I guess, my Violectric amp, being a bit on a warmer side, actually makes my Q701 more enjoyable, because it reduces that harshness.
Anyways, I'm glad you found a good fit for your preferences. However, you must beware of the need to upgrade . It can be quite a shock for your wallet .