I ran my Quark with just an added heatsink for a little while without the internal mod. Once I did it, I noticed temps were much better. Not only that, but it cooled faster. That alone tells me the thermal pad is not the best. Probably makes it much easier for the Quark tech guys to repair the ESC since the pad is so easily removed.
Yeah, I guess I should have said that 6s is "shaky". It really should be rated for 5.5s.
Many people won't want to bother to discharge their packs enough to get under the "Quark barrier", nor do many people have adjustable CC/CV threshold values.
The braking thing is no big deal really, just something to think about when comparing the pros and cons of all the ESCs out there. You really only notice the reverse-to-brake issue when moving backwards at a decent clip.
But, I do agree that it is VERY smooth. As long as you're not geared to the moon, you can crawl very slowly (<1mph) without cogging. And I like the low speed motor startup algorithm much better than the MM. It is my favorite ESC so far too, although I've never tried an MGM, only a BK Warrior 12020 and the MM.