I am not usually very fond of mocap animations due to the fact that they always seem to hit the uncanny valley for my part. The soulless motion of the maincharacter in Resident Evil Degeneration ( link) is a good example of what I mean. The animation is realistic, however, I feel nothing when I watch it. It might have something to do with the small details such as face animation etc, however, the run itself is so normal and smooth to me that I don't even notice it. I guess it depends on what you want to have in your game or movie. Maybe you don't want to have an interesting animation, since you don't want the audience to be distracted, and that is fine. However, if all animation is so plain and realistic that you don't even pay attention to it, I will be bored, even though the protagonist is a superbuffed viking smashing huge armies to dust with a thousand pounds big tuna.
I do know it is very possible to tweak that animation to something with alot more feeling to it. And I know there are some very good mocap animators that create awesome animation with a mountain of feeling to it. There are many pros for using motion capture in a game production pipeline, and I do understand why big studios are using it. It is very fast to get something working, and the animation itself is, especially on walkcycles, very good if you aim for realism. The equipment also gets better and better every year. Combined with some keyframe animation, I do believe the feeling that I talked about earlier can be acheived. And lastly, it is very handy to have a mocap file as a reference for your keyframe animation.
During the past few years, motion capture has gone from being super expensive and hard to come by, to something that is affordable by the normal taxpayer. What used to only be utilized by big studios, is now usable by everyone. To really point that out, I will later create mocap data using a Kinect that we bought today, and import them into a CAT character in 3ds max. I haven't really mocapped by myself before, so definitely some fun ahead ;)
