As far as being "worth it" WSD does not necessarily mean more expensive - in fact sometimes it means less than a comperable men's bike if you can believe the LBS. I was in drooling over a Ruby this weekend and he was of the opinion that they are selling it for less than a comperable men's frame (he thought the Tarmac SL - but after looking I'm thinking maybe not...., but the top end Roubaix - which is pretty comperable is priced at least $1,000 higher.)

Anyway - if you are little like me WSD is a savior - I'm too small for any unisex bikes, but many women are just fine with normal geometry. Its all in what fits you personally the best. Oh- and don't rely on fit calculators - I had one of them putting me a 49 which is way way to big - I ride a 44. Get fit by a reputable shop and test ride test ride test ride.