I\'ve seen some discussion about L2S vs EF4 on Stack Overflow back in April, when VS2010 was launched, namely:
Dump Linq-To-Sql now that Entity Framework 4.0 has been re
The company I work for is a $2.5B to $3.0B solar manufacturing company. We're using L2S for all of our next generation manufacturing applications. It's not without its warts, but we've found it to be fast (contrary to what many think), nimble and very easy to work with. We have no regrets. It does everything we need it to do.