I happen to own all three of these...The VModa M100, SOL Tracks HD, and ZO.....For use with the ZO, these are hands down the absolute best headphones to pair with the ZO...How do I know...I bought about 10 of the highest recommended headphones for bass and hard driving techno...Ultrasone, BD, Sens.HI-FIMAN 500..on and on...I bought them all at once so I could do a head to head comparison...and I can't believe how disappointed I was in so called legends like Ultrasone...at least when you try and push them hard, fast and punchy...maybe they're better at church organs or something...but they just sounded like sh*t, compared to the VModa and SOL....I congratulate you on refining your choice down to what my extensive and expensive research revealed...These two hps are absolutely awesome....through the ZO...me - my ultimate experience, is sending audio first to the Schitt Lyr, then to the ZO to do it's magic. Either of these hps are light years ahead of whatever the 3rd best hp may be....Me though,...I bought and KEPT BOTH, but when I really want the most horsepower I can get, I reach for the SOL Tracks HD...it's just does everything the V-Moda can, but a little better...also - the metal chrome of the full size V-Moda may look a little more " serious"...but it weighs far more than the SOL...You don't think you care ???Neither did I till I wore the V-Moda for a few hours and was wishing for the SOL..
Like I said, you can't go wrong with either, DO get the ZO, you may be thinking - let me see how I like the HP alone, then I'll decide if I think I need the ZO....Yes you will, you'll be very happy...until you hear just how that much better it can sound with the ZO, then- Once you have, you'll say...Sh*t...If I knew it could have gotten this good, I would have done it from the beginning...Spend a few bucks, get the ZO from the start, and once you hear your HPs with versus without...No way you'll send it back...You'd lie to your mother to make an excuse to keep it....One last thing, please don't try and save a few bucks trying to get a FIIO and think you're getting the "value" choice...I owned the ZO, heard users claiming how they liked their FIIO, and how smart they were for getting it instead....So I purchased a FIIO to see what the hype was about....My opinion at least...What a POS !!!...Will it make the volume a little louder...yes - but that's about it...The ZO pumps the volume more, but more importantly tweaks the quality and clarity and punch...It's a whole different experience....One last tidbit of advice, and this won't cost you a penny...play your music through WINAMP, download, install, launch - play music - then go to equalizer tab under options, pre-set/select preset, and choose " SKA "...It''s that last thrust that will make you blow your load ( sorry pc people )