Being a Giant dealer I may be biased... BUT. Consider this...

Most small bike shops will offer a 30 day tune up, and a lot of them- like us for example- offer free adjustments for the life of the bike.
ALSO any good lbs is going to do a proper fit on you. Make sure the stem and bar sizes are correct, and if necessary change out at minimal to no charge.
AND set up your pedals and shoes if you are using a clipless system.

The experience I have had with our local performance shop is that they are nowhere near that personal. AND an employee told me that they really don't like working on bikes, so they charge astronomical fee's for service hoping you will go elsewhere. I've also yet to be in a performance store and see them doing a bike fit. They MAY do it at your store, but I've never seen it at the local performance.

So even if you don't go with a Giant, I would make sure that you are really getting your moneys worth. As my mom used to say "no sense being penny wise, and pound foolish".
Proper fit is essential with a road bike. Don't skimp on that!!