In the absence of an objective definition of "well executed" I will give my opinion. Yes, Silverlight is well executed. I have done fairly complex apps in both

In the absence of an objective definition of "well executed" I will give my opinion. Yes, Silverlight is well executed. I have done fairly complex apps in both SL and Flash, and the SL experience was better. Some reasons: Flash is the 10th iteration of a platform on the 3rd iteration of a language, so Flash has several completely different and incompatible ways to do everything. Flash code must be written in ActionScript, which can be used in exactly one environment (well, not counting Flash Media Server). The SL platform, on the other hand, is much more recent and has the benefit of throwing away years of iteration on WPF and doing things "right" from the start. It is well organized, consistent, and performs well. You can use libraries from non-SL projects in SL without rewriting them in a dead-end language.