I can't say I have noticed any capping like suggested since my 100Mb upgrade from 60Mb.
What I have noticed though is my pings are higher, which does not make sense at all. on 60Mb I was getting consistently around 5ms ping sometimes even less! but since upgrading to 100Mb it is now around 10ms and sometimes higher - rarely lower. That's just me being nit picky though, other than that it is amazing and I am surprised I got 10Mb upload off the bat too considering most upgrading to 100Mb only get 5Mb right now.