Recently I read an article by
Sean Wildermuth concering the
State of Data Access in Silverlight 4. He provided an excellent chart outlining the Pros and Cons of each data access choice.
I encourage you to read the article, and
subscribe to Sean's blog, as it provides some valuable insite. I think this statement sums things up quite nicely:
The three options for data access are still the same "Web Services, WCF Data Services and WCF RIA Services". My major issue with data access today in Silverlight persists: there is no perfect answer. There is give and take with each approach and giving good advice about the right one is difficult.
Sean also provided a very nice chart that quickly outlines these options:
click for a larger view