I rode a manual bike for several years, and bought an e-bike about a month ago for my 25-mile (round trip) commute. It's been amazing. I still get cardio (albeit not as much), I don't have to change in my lycra, don't have to shower when I get to work, and the commute is actually faster than driving (the 101 sucks). I'll still do the occasional ride on my old bike, but it's mostly e-bike now.