One missing statement you may have noticed is; 'go out and try some hardware', this is not an option for most of us, sadly to say. Our resources are primarily reviews and sites like this with blogs, to glean what we can before making a purchase decision. Return policies are important.
I was just at a Best Buy looking at monitors and decided to check out the "Magnolia" section to see what cans were currently on display. What a disaster, jumbled and maybe 6 sets shown to try. For Sennheiser only the Momentum was present, and I went over to look at cables before leaving. A fellow with a badge was taking pictures of the headphone display, and I was looking at him doing so... wellll it looked a bit odd... so he kindly asked if he could help?... I said I was fine... then I saw the Sennheiser symbol on the badge and asked him if he was "Sennheiser?", he said yes... so of course I started questioning him about cans and where they are going with stores, "brick & Mortar". He said they are still trying to figure it out, 'Sennheiser is a very conservative private company and makes careful moves'. “They had the store in NYC but didn’t work out.”, really a SoHo location?... He did say that they intend to put HD660's in at least Best Buys, so that will be interesting. You may want to bring your portable rig though to try them out… Senn needs to have a mid-priced amp besides the "gaming" GSX one to put in these locations, as I am not impressed with whatever they have that you plug into… FYI; the Best Buy I was in, is in the second largest mall in America, and not so great, the flagship store in MN, next to HQ, is the nicest, for a BB.
Again I will say; don’t buy on power, buy on quality, but don’t under-power.