Have you run into any major problems with the Data Access Application Block? I'm not as worried about performance as I am for the current project I am working on. I really wanted to use Mere Mortals .NET, but the client doesn't want to support it.
Other than it's just a wrapper for ADO.NET - I do like Kevin's BizObj a lot more because they have the obvious New, Save, Cancel and Delete functionality built-in. It's great as a RAD tool. But I can't say that either Ent. Lib. or MM.NET are a good Enterprise Framework right out of the box.