I'm guilty of #4, but I think it's a judgement thing. If you're just going to briefly use the dictionary, I personally think it's a waste of time to go to the e

I'm guilty of #4, but I think it's a judgement thing. If you're just going to briefly use the dictionary, I personally think it's a waste of time to go to the effort of creating a class. If it's core to your program it makes more sense since you can then tap into things like KVO a bit better. And, prior to ARC and automatic synthesis of properties, it made for a ton of boilerplate code.