LINQ to SQL is pretty poor in my opinion, plus it's no longer maintained and bugs aren't fixed[0].
[0]: http://www.aidanjryan.com/blog/2012/08/25/sqlmetal-bug-with-...
[0]: http://www.aidanjryan.com/blog/2012/08/25/sqlmetal-bug-with-...
The initial version in 2008 was a total mess. It wasn’t until a few years later that the XML definition and code generation junk was removed and it became useable.