The semantics are pretty good with the IDE I use most often, IntelliJ (for instance you definitely do have marks, there is a sensible kill-ring-like functionality for M-y, etc.). Writing a custom function is harder (I think you've got to write an extension, basically), but there are a lot of other useful things you can customize (making up your own templates, for instance). Also, the deeper understanding the IDE has of your code compared to Emacs lets it make many more useful suggestions for issues and potential refactors.