sorry that your original questions weren't answered yet....

1) in terms of life expectancy, Al will have a longer life than carbon. Depending on your weight and type of riding (are you a stomper, do you race, etc) >> then carbon has a rather limited life. Most of the terrible things about carbon frames have been corrected. the trek OCLV for example used to have terrible frame problems early in their lives. Al will still last much longer. carbon can lose its already soft feel over time. Al keeps its ride characteristics well over time.

2) performance. i've never raced on either material much more than a few times, but both frames are toublesome if you crash. yes, with Al you will need your accessories (seatpost, fork, stem) to dampen road chatter. unless you ride on perfect roads, it will be harder to get a smooth ride (harder, not impossible)
When you stand and really get after it, an Al bike feels like its using all your powerstrokes>>over time Al will stand up to this test.

3) road conditions. see #2.

The weight differences are negligible.
Longevitiy issues are next up. I see a lot of Al bikes on ebay. they have good resale value. i am always leary of used carbon. i am leary of the change in joint strength over time.

its funny, because i had the same questions recently, but was asking the differences between steel and titanium. now that's a thread!!