One of the longest threads on the BobVila Fix-It For'em has to do with this topic. There are lots of opinions posted here, and if you look at Jay-J Moderator's response near the top of the thread, some useful links. http://www.bobvila.com/wwwboard/messages/42356.html

I have no experience with the siding and cannot make a recommendation; however it appears that contractor experience, reliability and service are extremely important. Be sure to request references, and check how long the contractor has been in business. Understand warranty limitations.

It is very expensive and you could have you house painted at least 3 to 4 times with regular paint.

It will not cure peeling paint and it may even make it worse as it is a very heavy coating.

Don't believe the stuff about it not fading for 20 years as the paint on your car is much more high tech than this coating and it will fade before then.

It is an elastomeric coating which was designed for concrete and stucco so unless you live in a house made out of either of those it was not really made for that type of surface.

The botom line is if sounds to good to be true it probably is.