This is the most awesome advancement to designer-friendly web technology I've seen in a long time. The fact is that
1. it's easy to integrate and use
2. it's packed full of features that everybody wants and reflect current trends
3. is well-written largely standards compliant code and
4. is free - blows my mind.
If someone blocks your Flash, you'll still get the non-swfIR'd image, which is great. This is progressive enhancement at it's best, just like sIFR is. If people have Flash, they get an enhanced experience. If people don't have Flash (or block Flash), they still get a good experience.