The main difference between riding a DF and a 'bent is the comfort of the 'bent. A sporty low racer or high racer will be faster, for the same effort on, the same route. So if you ride less hard, so as your journey time is the same as your Df time, you will arrive a little less damp.
Remember that, at first you will be slower on a 'bent. A slightly different set of muscles are used to ride a 'bent. People who are cycle fit already all seem to report aching muscles along the top of the thigh. Typical distances to 'get your bent legs' can be anything from 200 to 1000 miles. Also most people ride with a higher cadence on a 'bent than they did on a Df and this takes time too.
My experience as a regular leisure cyclist changing over in my mid fifties was that it took me a thousand miles or so to be as fast (or slow if you like) as I was on a DF. All my 'bents have been touring models, had I bought a sports model I would have seen an increase in speed. My cruising cadence went from 72 on a DF to 84 on a recumbent and I spin faster than that up hill. I couldn't/didn't spin like that on my DFs.
Also I find riding in the dark in rain difficult, as I have to wear prescription specs, and the combination of a lower riding position, wet specs and oncoming headlights is not a good one. Much less of a problem in well lit areas, though.
