I have a Brompton with a 3-speed hub and I continually find I want more gears as I never seem to have the right one. As they say, though, YMMV. If you live in a very flat area (I don't) then it may be fine. Personally I like my gears close together and always put the closest ratio cassette I can get away with on my road bikes. A Sturmey-Archer three-speed hub has around 33% gear inch differences which is a lot, and I assume the Nexus will be similar.