roughly identical. The SCA takes no extra place as it is set just above the flash shoe. The advantage is you can exchange it and use the flash gun with different camera makes. I am switching SCA adapters for Leica, Rolleiflex, and Hasselblad depending on need. This is a great and very reliable system and I would recommend it over any camera-specific solution. By the way, the latest Leica flash gun is also made by Metz. All Metz flash guns are produced in Germany.
I support full what this member stated and correctly pointed out the MANY advantages of Metz flash. You only have to buy SCA adapters to suit whatever cameras you have. They are not bigger than the Nikon SB flashes or the pro series Canon flashes.
I find the size of Metz "more" powerful per GN.
Sometimes, I would use my Metz on my Nikon instead of my SB for photo-journalism, esp when I need to bounce off high ceilings or side walls (as fill).
Each time there is a new camera/model on the market, Metz will produce a new SCA adapter for it to cover "new" technological features.
Pro level Metz is a good long term investment.
good luck!