i'd go for the Cannondale and fire on a set of Rockshox Revelations and an RP23 shock so it'll run with a 67 degree head angle and it will out handle the Giant easy! It'll also weigh a good bit less, that Giant is a bit of a porker in the weight dept.
But then I'm biassed with Cannondale's
(currently got a custom spec Cannondale Rush Hi Mod 1)
Personally wouldn't change a thing, the Leftys are great forks.
Just for the record after a bit of poking about it seems that Giant have had quite a few (especially recently) frame problems. All of my current bikes except the Marin have heen 2-4th hand and I have given them all huge amounts of abuse and not had a frame pop on me yet, although I broke a few bitd.
I think but may be wrong That Cannondale have lifetime warrantys on all frames apart from the Freeride frames which have 3 years
@ GradeAfailure: Just out of interest why would you need to change any parts ?