It's a hard call. A:M has far more rigging tools (constraints) available to it than ANY other package out there. This wealth of constraints really makes it fast to rig up some quite complex and easy to use rigs.
I've been using maya for about a year now and even though it's powerful I don't think it matches A:M's rigging out of the box. If you're a programmer and can mel script away you MAY be able to match A:M's rigs.
If not, you can still get VERY good rigs out of maya, they are just not as... clean... as the A:M rigs.
As far as smart skin... no. maya has no such thing. The paint weights are very good, but I would KEEEL for smart skinning in maya
If you move to Maya from A:M and you give it time you won't be dissapointed. You may be confused at first, but give it a chance... build a model, rig it, and animate it... Then you'll get the feel for it.
All the best...