My trip to the HE-5LE was purely by accident =O Many years ago I sold off my HeadAmp Reference and Senn 650 for an O2 and HeadAmp KGSS rig and never looked back. When the cable for the O2 finally had its fill of being yanked while trapped under my chair... I sent it off to the UK for a new cable and ear pads. While it was gone I bought the Concerto and HE-5LE as an interim rig and decided it might be fair to give Team Dynamic 2010 a chance to remove me from the Stax Mafia. Brought in a B22 and Senn 800 to round out the compare. Took very little time to know the Senn 800 and I wouldn't get along so off it went. Also noticed that although the Concerto is a good amp for the price, with the price ceiling removed the B22 is a better amplifier in that wire with gain sense of the word, most noticeably down low. So off went the Concerto. Somewhere in there the O2 came back... HighEnd Workshop in the UK did an awesome job by the way.
So here I am, on my left HE-5LE and B22, on my right O2 and KGSS. Honestly I could stop at either and be happy. I haven't sat down yet to do a formal compare/contrast but after weeks of non critical listening I'd say the biggest differences are the HE-5LE's greater bass extension with less impact and greater treble energy. Imaging is good but the O2 is laser precise with more air despite less overall treble heat. Guess the key word for describing the HE-5LE is natural.
My LCD-2 ships tomorrow so should make choosing the final all rounder interesting