I haven't used the MLX200, only the older MLX100. My experience with the MLX100 was that it was fairly simple to use. Basically, you teach it some points through a FactoryTalk View supplied runtime, write some code to move it to those points. Their instructions were pretty straightforward. I had absolutely zero robot experience, but I have quite a bit of experience with PLC's. I had it moving the same day we powered it up so I'd say that it's pretty plug-and-play.
My only complaints at the time was that the data structures were pretty massive and dealing with speeds and accelerations of moves can be tedious. Last I spoke with Motoman, they have addressed both of those with MLX200. I figured they had to do something about memory usage with MLX200 because the plan for it was that you'd be able to use it with CompactLogix.