Hmm.. Excellent review.
What a shame, I was hoping for another bass head casual listener headphone that would be quite (trans)portable, too bad.
I am very used to IEM's, so this is quite hard....
M50/SHR440/880's are too neutral for my tastes, and the XB500/700/1000 is just too large for my taste. No removable cable, or collapsibility.
750DJ's durability seems to risky. Not worth the risk IMO, especially for +$100
The HFI-580/780's cable is too long, I really don't want to have to braid my headphones, especially at this price range.
M-Audio Q40- not (trans) portable enough.Collapsible, removable cable, deep bass,very portable, I need transportable. Even M-Audio themselves said it
I was so excited the pro700mk.2's would fit my needs.... But following this review..... GAH.
There are no headphones that meet my needs... This audiophile business just isn't working for me.. -.-' I'm tempted to just blow off my cash on some Crossfade LP's...

If you need to use them for casual listening, then you might need to invest for $30 more in getting those beyer-dynamic velour pads to make them comfy. But, even so you'll still feel the head clamp pressure, it's totally different from the M50s; since the M50 have aluminum that bends and loosens over time. The Pro700Mk2s has a thick military-grade plastic for its band, so I don't think it will loosen up for a very long time. I have stretched mine on my speaker box for almost a month now and they never loosen up.
Anyways, if you want a bassy headphone with AT's signature warm mids, I suggest getting those WS55s. Also, the entry-level SJ55s is also just as good, but they don't offer the same removable cables and well-extended controlled bass like the Pro700Mk2s. So it's either, tucking-in some extra padding, getting beyerdynamics velours, or getting a generic 90mm velours on ebay. I could wear them with 1 ear DJing the whole day, but with two ears with no modifications or whatsoever? 30 minutes max.

I was considering purchasing these for casual listening but now Im having some doubts. Will the Beyer Velours make the headphones considerably more comfortable? How much longer can you wear them with the velour pads?

Thanks for replying...
Hmm... I am not sure if I want the WS55 or the SJ55's for the lack of removable cable. I know, stupid, but I have restrictions...
I think I will definently look into the beyer pads if I do end up buying the pro700's...
Wish there was better options but....
Also:
Just for confirmation:
These are bass head headphones right? I am scared it might end up the same way as the M50's.. ( People called the M50's bass heavy once!! )

Do you have a link for the Beyer pads?

I'm used to it and I could wear it for about 3 hours with velours, with the added memory foam, probably about an hour and a half.I have modded mine by adding strips of memory foam borrowed from my Philips SHL5500, I placed them on the driver shell itself, you can use some double-sided tapes to secure them. But, I prefer tucking-them in the ring where you secure the pads. With this mod, the bass has noticeably became more fuller and tight. Problem with pleather is when your ears become sweaty, you'll be having some rashes.With the velour pads, the bass weakened, comfort level is up there, but you will still feel the head clamp for sure. If you think the ATH-M50 is already too tight for you, this PRO700MK2s feels twice as much clamp. I don't really use them for casual listening, I just use them on my DJ gigs and let them rest in my dummy head when not in use.

This has the same signature as the XB500, accentuated bass, then flat on the mids and highs. I use my stock pads, I added 5mm of memory foam strips that way there's no loss of audio quality. I would suggest to add some foams first, if it doesn't work out for you, then get the velours.
http://www.google.com/products/catalog?q=beyerdynamic+velour&um=1&ie=UTF-8&tbm=shop&cid=10242439644538549218&sa=X&ei=G9lWT_STE6m5iQe5mZC2DQ&ved=0CCAQ8wIwAA

HDJ2000s velour pads on customcans also works they are circular unlike the beyers which are oval. The foam pad mod worked for me but still the clamp will not go away, you just need to get used to it. Audition with the Beats Pro, it's like that with twice the clamp. But, the Pro700Mk2s pads seems larger and they are totally an over ear for me.

How are these in comparison to the HDJ-2000's?

For DJ monitoring purposes the PRO700MK2s are better. They sound darker, better for high volumes, it won't fatigue your ears... bass is definitely strong. But with regards to casual listening, HDJ-2000s are better.