Very nice review...
I am about a year into headphones, so I can be considered a learning newbie.
With that said, I am mainly into bluetooth/wireless. My source, Samsung Note 4 and Tab Pro, both support aptx. My Note 4 has flac files galore.. My gym headphones for their clamping force are Harman Kardon BTs. My main headphones, and was my best are the Sony MDR 1RBT MK2, both of these support aptx. The Sony is way better than the Harman Kardon BT.
Moving on, I am/was looking for something that can best the good sound of my Sony MDR 1RBT MK2s.. So, I purchased the Definitive Technology Symphony 1 and the Sennheiser M2 Wireless.
Going to make this short. The Senn M2 blew everything out the water.. Going bluetooth the M2 was the clearest, sharpest, great separation, clear mids highs, the whole 9 yards..BTW, I am playing flac files off my Note 4, that supports aptx, just like the M2. In fact all the headphones I mentioned and have support aptx.
The Definitive Technology Syphmony 1, might be good, but it could not stand up to the Senn M2. In fact, my Sony MK2 gave the Def Tech Symph 1 a run for the money, an might be a toss up, or give the Sony the win..
The Senn M2 is a clear $100 more the Def Tech Symph 1, and I had to pay $30 tax on the Senn M2.. Still, I kept the Senn M2, and sent the Definitive Technology Symphony 1 back. The Def Tech Symph 1 were $400 opposed to $530 including tax for the Senn M2..
Bluetooth is my main priority, however, I did connect the Senn M2 up wired, OMG!! Then I connected the Senn M2 to my O2+ODAC headphone amp..OMG again. The Senn M2, just kept getting better, and better and the sound always makes me smile!!
IMO, Sennheiser M2 is the king of the bluetooth hill. And can rival anything in the $500 price class. All below that price point, can't touch the Senn M2 with a stick. Just my opinion..