We have a Moviecam SL and a Compact Mk2 in our rental inventory (as well as Arricams). They are first-class pieces of engineering. So well designed that (as you probably know) Arri bought the company in the 90s and used their ideas to develop the Arricam system. The heart of the camera, the movement, is identical to an Arricam movement, and many other aspects are very similar. The main difference I would say is that Arri's electronic engineering and quality control is superior, but that's hardly a criticism.
Moviecams have been used on a multitude of high and low budget features, TV series and TVCs. Some of the features include Aliens, Scream, Notting Hill, 21 Grams, Black Hawk Down, The Day After Tomorrow etc. I don't think you'd find so much industry acceptance if the system wasn't a very good one.
The only downside to owning one these days is the lack of technical support, since Moviecam Vienna no longer exists and Arri only supports the Arricam system. But there would still be some rental houses around that are familiar with Moviecams.