I've paddled both and they're very different.
BTW..Werner have a new smaller blade paddle now called the Carve.. I'm sure it's very good also.
The main differences between the Spanker and the Methane is.
The Methane feels lighter..Only a smidge because the Werner is also very light.
The Methane is more narrow in the blade and has a bit less blade area.
The Methane has a more rectangle feel in the shaft and also a bit thiner diameter shaft.
The Methane has a dead flat blade face but because it's narrow it does not seem to flutter.
The T grip handles are also different.
They both have a good flex or spring in the shaft.
Both are great paddles.. You can defiantly paddle with a faster rate with the Methane.
You can see by this pic that the Methane is a longer triangle/teardrop shape blade and the Spanker is a bit more rounded and fatter shape.
DJ