A lot of arguments from people uncertain how to do it in any app. Its futile to argue what app is better at an area you don’t fully understand. If the impression is that maya is specially suited for this type of rig, consider that the only three good examples I know of, of a rig with this sort of extreme cartoony flexibility, are all from Mindbender studios, it isnt hard to realize there is a particularly talented rigger or team of riggers there who specialize in this style and this is the fruition of further developing their cartoon network rigs from several years ago.
Talent, time and evolution, nothing to do with software. We can discuss simplicity of python APIs but you dont see a lot of character work coming out of houdini, so again it’s a moot argument.
The discussion on performance is a tough on in this case, as yes maya does have the ability to accelerate their character rigs with the GPU. However what is in a rig and what they call accelerating a rig are two very different things. Skinning deformation, ik solvers and rivets doesnt mean all types of deformations and blendshapes etc are,k and when you start to mix I custom expressions and such, you basically sacrifice that acceleration for functionality. I highly doubt the is a big performance difference with and without the GPU acceleration of a rig like this based on the extensive benchmarking I saw while at Dneg.