I popped into my local Specialized dealer, a bit of feedback on the Vado SL:
The Vado SL has carbon forks, the cheaper model does not have any suspension, the top model has 20mm of suspension built into the headset. The other key point is that the Vado SL is lighter than the Vado not only because it does not have forks, but it has a smaller motor with half the power and a smaller battery The range is the same but the SL does not tackle hills with the enthusiasm of the Vado and will require some manual help on steeper hills. The dealer says it is brilliant on towpaths etc. The additional power pack battery fits in a bottle cage and is easily removed for charging in a Motorhome and the system can be set up to use that battery before the built in bike battery.
The Vado SL has carbon forks, the cheaper model does not have any suspension, the top model has 20mm of suspension built into the headset. The other key point is that the Vado SL is lighter than the Vado not only because it does not have forks, but it has a smaller motor with half the power and a smaller battery The range is the same but the SL does not tackle hills with the enthusiasm of the Vado and will require some manual help on steeper hills. The dealer says it is brilliant on towpaths etc. The additional power pack battery fits in a bottle cage and is easily removed for charging in a Motorhome and the system can be set up to use that battery before the built in bike battery.