Technically I don't know how SL stacks up against Air or Flash but it seems pretty obvious to me it's not a good idea to trust a company that has so much to gain from making a technology popular and then slowly pulling back support to promote their operating system & web browser and, by extension, their own web services.

I don't particularly like Adobe but their cross pollination of Flash to the Creative Suite is not a deal breaker and they, of course, have every incentive to make Flash run on Windows, OSX, Linux, mobiles, etc.