I would quit looking down at the TT and look ahead at the road. My three LOOK frames all have sloping TTs and I never think a thing about it. The ride may actually be better (compared to the LOOK KG381 and two Colnago C-40's I've owned). Of course there's more to the frame differences than just the TT slope, but my KG461 and two 585s all ride better than my earlier carbon frames.

I'd buy whatever feels best (if you can test ride) or fits best and forget about the TT slope.

I would expect that the amount of seatpost flex would be the only difference one could detect between otherwise identical sloping and non-sloping framed bikes.
But people buy bikes that appeal to their sense of aesthetics. That's what this thread is about.
http://www.cyclingweekly.co.uk/image...30d7f0a866.jpg

Another choice - Bianchi Cross Concept. Full carbon cyclocross, Ultegra/105 mix, very sharp.