Looks like a sweet press for sure. Seems like the huge sprocket would be a great idea, that much more area to spread the indexing forces over.
And actually, M&R IS using a chain drive indexing system--just not on a round press.
Their oval Alpha 8 has a pretty beefy chain drive, IIRC a similar design independent of registration.
As far as wear with chain and registration, I don't see how it's likely to be much different than any other servo drive--it'd be truly amazing if they didn't have a way of calibrating where the beginning and end of the indexing motion is.