Be excited and not scared.

I would recommend that your sales person is a certified fitter so that maybe they can throw in a qualified bike fitting for free when you buy your bike.

I love my Amira and feel that the handling seems less ackward than on the Ruby. Also, you might want to get the carbon handle bars to decrease road vibration. Because I changed stock immediately before I took the bike out of the store, my very nice local LBS gave me some store credit back for the stock alloy handle bars and for the handlebar tape (I changed from the white stock handlebar tape to black).

However, there are a lot of Ruby lovers and Cannondale Synapse lovers out there. So enjoy trying out all the bikes this weekend. Maybe if you can write down what city,state you are in, some of the Team Estrogen members can recommend good LBS shops.
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2012 Specialized Amira Elite, upgraded carbon handle bars, Jett saddle 143mm

2011 Specialized Ariel Sport,suspension post,Serfas Rx Women's Microfiber saddle