I have mostly seat-of-the-pants comparisons in that regard, with no real data to accurately answer your question. I will say that, outside a couple of times trying it out, I NEVER rode my standard Vado without assist. It just wasn't pleasant. The couple of times I tried to do it (over about a mile of flats each time) not only did I experience noticeable drag in pedaling (it felt like cranking down the resistance on a stationary bike), but I also believe (based on my TCD data) that my battery continued to drain, even when I had the bike off and was pedaling unassisted.
Because of this, I didn't experiment with it much beyond those couple of times and resigned myself to always riding the Vado with some assist in SF's frequently changing elevations. That is not the case with the SL. I frequently ride with no assist and almost never ride with Turbo, except on the steepest climbs or mixing in heavy city traffic.
As such, by my estimate, I get as much as 30-40% more range on the SL. Again, that's not based on hard data, it's based on the number of times it's been necessary to recharge after covering my same commute route.
That said, the Vado was faster. It was quicker off the line in traffic, too, which is safer for city riding, where no bike lane is present. The SL is more maneuverable, though, and handles more predictably. It's also easier to bunny-hop over streetcar tracks or up curbs, when necessary. The SL is the better road/commuter, while the Vado has the edge as a gravel bike.
There are a few street conditions in my area that give the SL a pretty good shaking, but were barely noticeable on the big Vado. With its longer wheelbase, heavier frame, big suspension forks and more powerful motor, the Vado would speed right through... I hate to say it, but almost like a motorcycle. It's an awesome ebike -- to me, one of the best all-around -- but in my case, I felt like it provided too much boost in every situation where I wanted it to be a bicycle, or at least a lightly assisted bicycle. IMO, the Vado is designed to be primary transportation--a pure car replacement--and it serves this function well. It's a bit power-hungry with regard to the battery usage, though.
The SL is a bicycle through and through. The joy of cycling is there. The convenience of an Ebike is there. It's not as fast as the regular Vado, but it's only a step slower. For riders who know what they're doing, it's equal to the Vado on most elevation changes. And the greater effort required to climb the steepest hills or maintain speeds in the upper 20s is exactly what I wanted in an Ebike.
