I'm guessing here as I have never heard the 600, but the 650 and the 660s2.

IMO the bass on the S2 is much more textured, in a dry and less fuzzy way and the subbass extension feels better. The 650 sound more like a relaxed jazz sound. I'm guessing the 600 land somewhere in-between and might have been a very good option for me, bummer, but i still very much prefer the S2 over the 650.

I'm guessing the reviewer's assume that everyone bought the 650 and 600 based on what they preferred and want to say if you prefer the 650, the S2 isn't for you, and if you have the 600 the 660s2 isn't a worthwhile upgrade, but as a (maybe, idk) 600-person stuck with the 650 these sound great to me.

Why are you so comfortable in criticizing him for buying the S2, when it is better than the S1 which you own and I'm guessing paid more than 600/650 money for, when you by your own logic have the worst of the bunch for the second highest price?

I have the HD650, tested the HD660S1 and just received the HD660S2. To me it is a definite upgrade over the 650 as I vastly prefer its clean, clear and detailed sound, I never quite came around to the warmer sound of the 650 and eq didn't solve that. The 600 might have been the best price to performance for me, and I might even go for them still once I sell my 650, but saying he's wrong for enjoying them doesn't make any sense, especially from your standpoint.

That was in no way sarcasm! Southpaws are few and far in between

Where is this magical place where one might aquire one of these?