Just on thursday i decided to pull the trigger on the HE-400i's to replace my current open backed headphones HE-400.  I guess im still in the buying mood cuz i just picked up the NXT Audio XPT100's for $80 + $5 shipping to Canada from Buysonic. 
 
Not sure if i made the right call here Damn that super cheap shipping.
 
My current closed set i use for work are the Logitech UE6000's - im not sure if the NXT's are a clear upgrade..it just might be a more neutral version of the 6000s. 
 
Was originally thinking of the NAD HP50s, Focal Spirit Pros or Classic as my closed can upgrade...i'm thinking i want to increase clarity/separation/soundstage and if possible recreate the 400i sound in a closed form factor. 
 
Should i cancel?

The XPT100s have decent clarity and soundstage, but they're on the dry/somewhat sterile side.  I haven't really heard the 6000s, but if they sound how I imagine, you might miss some of the warmth/lushness.
EDIT:  I've tried a lot of headphones around that price range, and I've found that the AKG K 550s do a lot of things very well.  Excellent clarity and soundstage, but they have a nice amount of midrange warmth and do not sound sterile to my ears.  They replaced my SoundMAGIC HP100s, which are excellent headphones in their own right, and which I owned three separate times. I think that the bass of the K 550s is going to be lacking compared to the 6000s, though.

tl;dr It's good. Cancel anyway.

XPT100 is much more comfortable than the others you're considering. It's also more durable. I've gone through so many closed headphones that I'm embarrassed to say, and I have yet to find a better fully closed one under $400-500. You might want to tape a small circle of soft or stiff felt (depending on your preferences) in front of the driver to soften the treble--not that it strictly needs it.

Soundwise, the Focals are very good, a totally different league. But fit is very poor as is build quality. Fail.

I rather disliked the NADs. Yes, they're more speaker-like, just not enjoyable because too strident. Fit is below average, and I wasn't impressed with the build quality either. Near fail.

But I can't answer your other question. It's been too long since I heard UE6000. XPT100 is certainly more neutral. I don't know which you'd enjoy more. My instinct is say save your money for a bigger upgrade later like ZMF Vibro.

Dammit - i mustve missed this - the buysonic processing email just came through lol 
 
Im not sure i can cancel now 
 
How would you think the NVX's compare to stock Mad Dogs? I have an offer to trade my HE-400s for them. 

q2klepto said:

How would you think the NVX's compare to stock Mad Dogs? I have an offer to trade my HE-400s for them.

Click to expand...

I'm a fan of stock T50RP mods for what they are, but HE400 is better so I'd stick with that. It's been a while since I heard MD but it's a lot more laid back and smoother than HE400.

claritas said:

I'm a fan of stock T50RP mods for what they are, but HE400 is better so I'd stick with that. It's been a while since I heard MD but it's a lot more laid back and smoother than HE400.

Click to expand...

 
I suppose a the NVX for closed and 400i's for open would be the better choices. Ill try and get cash for the 400s. 

Those are both nice choices. Depending on your preferences, HE400i beats everything in its price category except HD6x0 + tubes.

FYI, I'm now using a version of this this mod for XPT100. I'm hearing more low bass, which nicely darkens the sound a little more. But it's optional in my opinion, whereas the front damping increased my initial liking for it.

FWIW, I preferred the Mad Dogs (Version 3.2 with Alpha pads) to the HE-400s.  The 400s sounded weird, kind of muffled and veiled.  It wasn't terribly pleasant.

Yea these would be stock Mad Dogs with stock dog pads (or whatever its called).
 
I contacted buysonic, and they said the NVX's have been packed so i cant cancel Oh well - i guess ill use the money from the 400s for something else...like winter tires. ;/