I thought I'd look at the Electrovoice RE20 and the SM7B, both coming from the broadcast industry where radio in particular needed mics where the talent could move around a fair bit without the tone of the mics changing very much. I've seen quite a few videos on Youtube where people have mentioned proximity effect without really explaining why a mic that doesn't change tone as you get close is important. 

It's not a comparison between the mics really - just observations on how they both work in practice in ways that help broadcasters, and now podcasters. 

I've tried to walk a fine line between too technical and not technical enough - but hopefully for those interested in why these mics are considered 'special', it should work ok.