They are comparable in that they both take up space. Similar to other small appliances. I don't use the microwave much at all when hubby is home and I'm not living off microwave meals.
Mostly I'm reheating lukewarm coffee, that's all and given I'm not much of a coffee person, I don't touch the stuff when hubby's home, I have little need for one. Personally I prefer to steam. I don't like clingfilm because it still isn't biodegradable in the vast majority of cases. Thankfully the stuff I have is better that traditionally stuff but still not fantastic.
Plus most of my 'greens' tend only to be blanched or added to other stuff during streaming or cooking. Saturday night peas are an example, they just get boiling water from the kettle poured over them and then left. No extra heat needed. Leaf greens are usual eaten raw or just blanched. Again just pour boiling water over and leave.