Very little between the bikes but there will always be one that grabs you and says "BUY ME"

I was in a similar situation this year but did my testing last Autumn. When I went to order the Giant I wanted--NONE were available. They were but not in my size or in a price bracket I could not go to. However- I had tried a couple of the smaller Manufacturers in a Pinarrelo FP1 and a Colnago. They were a different beastie compared to the Big Name bikes and were not that expensive for the quality. Went for the Pinarrelo and not regretted it. Might be worth having a look at some of the "Performance" manufacturers for a pleasant surprise.

But staying on Giant--Have you thought or tried the TCR Composite range? That is one bike I am settling into for comfort and handling.