It's highly unlikely that you'll find anyone who's knowledgeable as to both of them. A quick check turned up this "shootout" which included a M3 and a HTD, and which might interest you if you haven't seen it. Knowing the quality of the M22s, I'd doubt that HTDs could match them, except for presumably having more bass extension, but that's just a guess.

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Enjoy the music, not the equipment.