Sound
 
First off, I do need to stress these sound excellent. Excellent clarity, great bass, fun and a neutralish sound that is enjoyable for long-term listening. I think they need a bit more treble but I can certainly see how many people think the treble is there in just the right amount.
 
However, the real let down is the many design choices that really harm this headphone.
 
On-ear or Over-ear?
 

1. For the average ear these are on-ear headphones not over-ear. The ear cavity is far too small to fit the average ear inside. The ear pads also take up half the potential space.
   
   Inner cup dimensions: 48mm x 38mm
    
2. The pads are glued on. They can be replaced but you will have to rip them off the glue first. See this link for pictures. This is absolutely not ideal with a headphone that already has a critical flaw of a tiny ear cavity.
3. If you have hair over your ears then these are not going to stay on your head if you are moving around.
4. Even though the pads stick to your ear I wouldn't be confident running around in an outdoor environment. For outdoor professional use they simply have to be over-ear and you cannot worry whether your headphones are going to fall off.
5. Isolation is pretty good.

 
Comfort
 

1. I wear glasses and am able to wear over-ear headphones for hours on end with them on. Within an hour the top of my ears are starting to get a bit sore and I find myself trying to readjust them to get them comfy.

 
Build Quality
 

1. This headphone has the remarkable ability to somehow feel solid and yet rattle if shaken. The key problem is the arm design which rattles and this is probably going to be the point where these would break.
2. Ironically, it's the metal joints that connect the cup to the headband that feel the flimsiest on these headphones. They have give in directions they shouldn't and this is the main contributor to the rattle like quality of this headphone.
3. The arms do swivel and mine has a squeak squeal. Not terrible but not confidence inspiring either. The squeal is by far one of the worst sounds I've heard. It's a loud metallic squeal from a joint that that connects the headband to the cup and it happens every time I readjust the cup. Lubricating the hinges that connect the cup to the headband has stopped the metal squeal.
4. Anything with the black waterdrop paint is plastic. The top part that says 'professional' is some kind of rubber.

 
Aesthetics
 

1. There is a sacred rule in good headphone fashion design that the headband and arms should not stick out from the persons headphone. The headband should follow the curvature of the head. It's the difference between this and this. Focal breaks this rule with the arm design which makes them look goofy and unfashionable. In an age where headphones must sound good and look good this is unacceptable. You'll also note that all images of the Focal are done from an angle so this goofy headband design is less noticeable. If Focal wants to look for inspiration then they should start with the Sennheiser Momentum. Just try and keep the headband flush to the head.
2. Water drop finish is pretty nice and has a slightly bumpy texture. Personally, I think the finish would look better if they went for a black aluminium style finish instead. I don't care if it's metal or plastic as long as it feels sturdy and if using plastic makes the headphone lighter and cheaper to produce then I don't have a problem with that.
    

Miscellaneous
 

1. Headband slider has no markings and the slider doesn't have a solid click between each setting. It's annoying and difficult to get it in the correct place each time.
2. Has a detachable cable. The 3.5mm socket in the headphone can only accept a connector housing that is less than 6.04mm. You'll need to make sure the cable you are using has a slim connector housing.
3. Excellent for gaming with sharp imaging and yet still has that fun bass. For competitive gaming I'd EQ up the treble and EQ down the bass.

 
Overall Impression
 
It's a real shame that such an amazing sounding headphone has these design flaws. For professional use I believe a headphone simply should be over-ear and for outdoor professional use it absolutely must be over-ear and have a good clamping force.  For portable use it must also look good and this 'signature design' from Focal is simply not fashionable.
 
From a sound perspective it is excellent. Superb bass, excellent clarity and sharp imaging. However, from a design perspective it is poor. I hope Focal in the future re-evaluates their design because these are serious problems that can't be ignored. It feels gutting to write this about headphones that I enjoy so much but I believe that Focal is one of those companies that strives to be better.