I'm not well qualified to comment but from experience I can say that 'fit' is important and I also think it is wise to err on the small side as you can extend reach with a longer stem say 90to 10 or 100-110 but trying to reduce reach back to 80 can cause problems with twitchness. Most bike shops, sadly, still think women have the same reach and flexibility as men so tend to size you according to the other sex. My current bike, a little over 12 months old, is just a touch too small, I'm extended with straight arms when on the hoods and riding in the drops is not comfortable as deep drops and also hard to see the road and yet it's not set up as an agressive style with the stem raised. I guess my advise is to make sure you test a size smaller than people may recommend so you get a 'feel' for the differences in fit.

Also, good deals can be had in bigger centres and you feel great getting a killer deal (I did this) but paing more and buying locally can helps should something go wrong or the bike requires a bit of tweaking due to discomfort. Hard to stomach an extra 400 odd smackers and I loathe buying from somewhere at full price when others will discount but I am likely to do this when I purchase another bike (smaller frame -10mm smaller) in the coming weeks. Just my 2 c
Hope this thread is helping with the background research, cycling is fun when the bike fits and you suffer from no discomfort. I have a mountain bike that fits the bill and whilst 5 years old now it is 'heaven on earth' as far as fit is concerned.