Cannondale never lists weights. The one blurb I saw said 16kg - so not super light but light. I think it may be the same frame as the drop bar Synapse.
FWIW - I stopped at my local shop this weekend. It's clear that the brands see light -upper 30s to low 40s - flat bar bikes as a growth market. They had all the new SL2 models, a couple Trek FX+7's, a couple Tesoro Neo Carbons, and a flat bar Skitch all on the floor. Oh, and no less than 11 dusty original Vado SLs
From a purely visual standpoint the Tesoro Carbon was probably the sharpest looking, though I thought its fenders aren't a good match. The Skitch is very appealing in a no nonsense kind of way - it just looks fast and comfortable enough and like you can swap out whatever you want easily enough. The Trek just confuses me - I have a hard time with that stem and handlebar.