Where's your promised "report"?
Oh yeah, here’s my impressions of the difference:
I put 1500 miles or so on a Vado SL 4.0 (XL), then decided I missed the subtle difference of a full-on road bike so I bought a creo carbon comp (XXL) at the 25% off sale price. I have over 1K miles on the creo now so I do have a good feel for the difference.
The VSL was a nice bike and I would still be happy with it if I hadn’t gone for the creo. The creo, however, is more enjoyable and I ride farther, a little faster, and work harder on it than I did with the Vado sl.
The geometry difference is more than just the difference between drop and flat bars. My position (and I had a fit done on both bikes) is subtly different, with a little more bend at the hips, as well as the change in upper body position due to the stack, reach and bars.
I missed the feel of drop bar hand positions on the VSL, even with both outer and inner bar ends on it, and the creo seems to encourage me to work harder. I use a lower eco setting on the creo and my average power output is higher.
Some of the difference is in my mind - I feel like I’m on my old road bike on the creo and I ride it like a roadie rides. The VSL always reminded me that I was riding an urban flat bar/commuter, which is fine but made me miss my road bike days. I found myself trying to lean over more and more, spending more time on on the inner bar ends to get closer to a road bike feel.
So, both are great bikes but the creo is a step up for me and its relaxed geometry enabled me to find the right compromise between aero and comfort that works for me.