I have two swytch kits for the 2 bromptons that I have. While you could install the kits yourself, I went to a brompton specialist that was familiar with the kits and their install. Pros: It is a cheap retrofit kit that is of decent quality. The battery lasts a long time, and the wheel hub puts in good work. I honestly leave the power on the lowest setting and that is more than enough to make the battery last a long time and get you up hills with ease. The fold still works with some caveats that I will outline in the con section. Cons: It does add a bit of weight to the bike. There are some variances with the part quality that might make each install different. The quality of the pedal sensor is questionable. For this price, I would gladly pay an upcharge to a torque sensor vs the way Swytch did it. The sensor can easily loosen or lose its calibration if it gets lose during normal vibration and you need to reposition the sensor back it where it was. If you think it isn't working well, just push the sensor close to the detector and it should work again. Inconvenient but it is what it is. The extra weight on the bike makes it difficult to roll the bike when folded. This is true even if you use a rack and have ez wheels (or equiv). The extra weight causes the rear tire to push down more on the rear rack which causes the wheel to poke through the rack (if you don't have the official brompton racks). This makes rolling impossible. The bike still stands on its own, but it also makes having the rack extender shafts mandatory so the bike stands straight. Misc: I had to contact customer service because I ordered 2 full sets of the Swytch kit and I was mailed like 3.5 sets. If I didn't contact customer service, I could have unethically kept them and sold them for a profit. Instead, I contacted them asking what I should do and I had to unpack everything, double check my invoice to make sure I had everything, contact them to make sure I wasn't sending out anything I needed, and then mail the remaining parts back (Swytch did pay for return shipping). There is lag in the communication, but if you go into it not expecting 5 star customer service, then it is ok. If you can't get the ARC kit because you don't live in the UK, the Swytch should be on your list. There are other players in the Brompton space now, but I still think the Swytch is a good offering. It is a solid B. With a few changes and improvements, it could be a B+. I would rate the official Brompton electric as a B+/A-. ARC would be an A+.