I want to add validator attributes to my domain models (in an ASP.NET MVC app), and I'm trying to decide between 2 frameworks, the Validation Application Block and DataAnnotations. They appears to do similar tasks, so I want to pick the one which will be the most supported/used in the future. It seems DataAnnotations are newer (and built into the framework as of 3.5 SP1), so do people think the Validation Application Block will become obsolete?
[Marked as Community Wiki as this is subjective]