Putting free open source ORM/DataAccess/Modeling tools (like NHibernate) aside, what do some similar commercial tools offer beyond what the current Entity Framework 4 (plus CTP4) offers. Commercial ones in mind are Telerik's OpenAccess, IdeaBlade's DevForce and LLBLGen Pro.
Instead of asking separate question per product, I have them all here. If you have practical experience with 1+ vs EF4, I would like to know what features were of big benefits. Plus any serious limitations.
LLBLGen is a far more stable and mature ORM than EF4, plus it is extremely easy to use. You simply design your database (or use one that's already designed), and you're up and running. We started using it 6 years ago, and even with the old version we were up and running in literally 30 minutes.
There is a complete comparison of Telerik OpenAccess ORM to Entity Framework 4 on the Telerik website.
Clearly, you're likely to treat that information as biased, so you can find other non-Telerik opinions on other StackOverflow threads:
Is Telerik openaccess ORM worth learning?
Compare and Contrast NHibernate and OpenAccess from Telerik
In general, OpenAccess is more mature solution than EF (OA's roots, like NHibernate, trace back to Java) and with 3 major releases per year, it's constantly adding more features and database support. Today, OA supports a litany of popular databases, including SQL Server, Oracle, MySql, and SQLite, and it offers innovative features like the new Round Trip Mapping (forward or reverse map at any time).
Also, don't miss the fact that there is a FREE version of OpenAccess that can be used without restrictions on any free database (like SQL Express):
