carbon vs. aluminum frame

I just wanted opinions on whether switching from an aluminum to carbon frame would be worth the investment - Currently have a 6 year old Giant OCR 1 ( 105 components)  Just saw a great deal on a 2006 Giant OCR 3 carbon frame - with pretty much the same components (obviously newer)  The bike is on sale for 1350.00.  I love the giant compact frame especially since it is easy to throw on aerobars and adapt to a tri bike.  I ride a lot of hills / mountains living in Colorado.. For those of you that have switched from an aluminum to carbon frame - does this seem worth it to purchase the new bike?  I am about 220lbs and the limited test ride that I did sure seemed a lot smoother.but maybe it was my imagination...and how are the carbon frames for climbing..Thanks for any input.