In most companies you have product development teams who work out what customers want, and designers who will tell the developers how to make things easy to use, and support teams who deal with customer enquiries and write manuals. There is no manual, and it's pretty technical. The higher-resolution RAW functionality is still quite new, although lower resolutions are pretty well developed now, so there's the risk of bugs. There has been some buzz around ML killing SD cards or other hardware, but the reality is that this has happened in very few instances and isn't really something you should be concerned about.
Depending on what features you use, there may be risks of errors or bugs, or in the bleeding-edge stuff, potentially crashes and loss of footage. Each of those versions can contain features that are fully-tested and bullet-proof, but may also have features that are cutting-edge with limited testing or even bleeding-edge with zero testing. It's a modular software system with different versions across different camera models. People who obviously haven't shot with ML keep telling newbs to buy an Eos M and shoot raw with it - and this is a truly horrible thing to do. Unless you actually know how it works in DETAIL, you've read and understood what the OP is asking for, thought things over, and it's fit.