Yes, most people don't even know that Expression Blend exists. The first time I used it to customize my UI in Silverlight, I was blown away how quick and painless it was. To simply change the look of a button in Android, I had to spend far too long creating .9png files or w/e they are called.
I have developed for Android, and recently started developing WP7. So far, I prefer the development environment and tools for WP7. Silverlight + Blend studio allows for quick and beautiful apps, and XNA studio does much of the work necessary to get the frame updating and rendering working. So far I am impressed with WP7.