For folding bikes, which is all I own, I find the weight on commercially available ones to be too high to benefit from the all the nice things about folders. They are more compact but still fairly heavy to put in your car, a pain to carry up stairs, etc. In my mind, I separate out the fat tire big battery folders as different where weight isn't an issue, but for regular type wheels/builds for transportation the weight can matter. I prefer using an add on kit with a good folder - either a Bike Friday or Swift or Brompton. You can get BF down to around 15lbs (pakiT), a Switft with modifications under 20lbs, and a titanium Bromton around 24 lbs. Add on a good kit (anything from <5lbs for a OM friction drive to <10 for a hub kit) and your folder is still around 30lbs maybe under. When you're lifting it into a shopping cart at Costco the weight matters. I took my Dahon Mu Uno and Travoy trailer to Costco yesterday and stupid me forgot my lock (I lock up my Dahon; never lock up the Bike Friday). Even with the motor and battery, the Dahon was 27lbs so I could fold and lift into the cart. I swapped out just a couple things on the Dahon to bring it down to a reasonable 22 lbs (got rid of the pump seatpost and heavy saddle). One of the nice things about folders is not having to carry a lock (or not having to go home if you forget).