I would not use ADO.NET vNext in a productive environment. It is in a very early sphase. Also thr required LINQ Preview is old (last one is from May 2006). I don't know the O/R Mapper you mentioned, so I can't say something about this. But when MS releses the final in .NET 3.5 or 4.0 I will use it very soon In combination with (D)Linq it is cool