I have found two libraries to be extremely competitive and much better then fabric.
Kinetic.js and easel.js both have extremely good event handling, grouping and general shape abstraction. You'll find a lot to love in both of these; easel seems to have more image oriented and filtering.
Fabric's event handlins is MUCH worse than either of these - basically it treats the whole canvas as one big event rrapper and tells you when "Something" has been clicked on. It doesn't attach events to individual shapes or groups of shapes.
