I\'ve been dealing with Core Data for the first time and I wanted to know what the best practices are for extending the classes that Xcode generates for my NSManagedObject e
Now that you have posted your question as an answer on my question, I thought I should answer your question :)
Mogenerator doesn't look bad, give it a try.
Also the way you suggested with categories is also a fine option.
Infact here is a link that exactly explains How to do so.