My wife & I just had our house sided with vinyl (over old ceder shakes) and did quite a bit of research. To sum it all up, aluminum siding is on it's way out because it chaulks (finish powders) and dents easily. Although there are different grades of vinyl siding, generally speaking vinyl siding holds it's color better, doesn't dent and shouldn't chaulk. Years ago, vinyl siding got a bad rep because it faded over time and could crack during extreme cold weather. Those problems have been addressed. I suggest you check with Consumer Reports - they did a review of vinyl & aluminum siding sometime within the last 12 months. As with most anything, the quality of the installation will play a big part in your level of satisfaction - get references and research those references (drive by their jobs and talk with previous clients). You'll be looking at their workmanship for many years to come - take the time to pick a good installer! Also, several manufacturers now produce vinyl siding and accent pieces that look much more like real wood than ever before. If you're concerned about making the house look like it's got original wood siding you'll want to look into these manufacturers' products (I used Wolverine's Restoration line & am extremely pleased). If you'd like more information, I'll be glad to Fax you what I have (articles, reviews, etc.).