I love my Swytch conversions
I've done two Bromptons. The first has been going strong son early 2020. I've gone over 3000miles on the second Brompton this year. The power is smooth and enough to get up the steepest hills. I ride everywhere in our city daily errands and for pleasure. I also tour, this year the Empire State railtrail in upstate New York. It's reliable. I take planes, trains, buses. The Air battery (90 watt hours) can fly on planes, a big bonus for travelers! 4 friends have them, on my recommendation.