Zombie thread... AWAKEN!
Actually, I just stumbled on your thread when it was suggested at the bottom of the PM-2 Reviews section.
Thing is, there didn't USED to be many options in the $700 range, but these days there are a few more. Off the top of my head, I can think of the PM-2, Sennheiser HD700, the ZMF closed headphones, MrSpeakers closed headphones, HiFiman HE-560, Fostex TH600... you may notice a trend that many of these are Orthodynamic/planar headphones. I should also mention Stax as they have some models in this range and can be used with speaker amps and a transformer. This is by no means an exhaustive list, but the sound signature varies wildly from sparkly to thick and bassy.
You've really gotta think about what sound you're going for, and what environment, before you spend big money up in this price range. At least, that's my opinion. Audeze EL-8, Senn HD700, and that Audioquest Nighthawk all have a rollercoaster of spikes and holes, where they will sound great with some tracks, perfect with a few tracks and your right mood, but sometimes they just won't suit the music. Stax are fast, detailed, and effortless, really a breathtaking and "next level" experience, but Stax just doesn't understand long term comfort. The HiFiman I haven't heard extensively (though I may get to borrow one soon), but I definitely notice headphones that weigh upwards of 400g, and the HE-400 I DID hear needed a powerful amp that has extra forward mids to counter how the HE-400's comically v-shaped sound signature and make female vocals not sound like background vocals (and never have I heard such an open headphone so affected by proximity, aka if a wall or my hand is within half a foot of the earcup while wearing it changes the sound).
I loved the PM-2. It's a fast, detailed headphone with IMO no problems. It's lightweight, the sound is balanced with no harshness or distortion, I like the pads, and it's super easy to amp (though it scales up with a good DAC). I have a review of it in my signature. I love it's balanced sound signature, but honestly, from your music and sound preferences, you might get more "fun" and enjoyment out of the ZMF Vibro Mk II.
I'm borrowing a Vibro MkII right now (for review). It's a big, closed headphone, with beautiful closed wood cups, but it's also under the 400g weight and does an excellent job of distributing weight. Earpads don't itch, I only start noticing some discomfort after 4 hours but I can wear them for 5 hours or longer before I want to quit. For a sound signature, it definitely has a modest but noticeable bass boost, but it's extended and very clean, and the rest of the frequency range slopes gradually down from there till you get to extended highs but those highest highs are still clear and only a little below neutral. Just enough to take the fatigue off. A realistic feeling of timbre mates so so well with acoustic guitar and cello, feeling like a very rich sound but the Planar technology in the drivers means they're fast, meaning you don't have the bass bloat mush over the details and feel thick (like the Sennheiser HD700 did with bass and lower mids, because that was a slower headphone). The only thing the vibro does just good instead of excellent is the sense of sound coming from outside the earcups... you definitely feel like you're listening to headphones, BUT it has great imaging and you can still really sense the space between instruments where they are recorded, and has better than the average soundstage you'll find in a closed headphone. You'll also want to have an amp... Good volume for me is 3 boxes below max on my iPhone 5S, but almost everyone I shared it with at work turned the volume up to full, and a good amp with lots of power headroom helps the sense of dynamics and depth. It sounds great with Rock, Jazz, R&B, Hip Hop, and yes even Pop. My opinion, for what you said, I'd recommend the ZMF headphones Vibro Mk II.
