Please look at System.Data.OracleClient Update for more information. In the pasts, I have used ODP.net and have found it better than Microsoft Client for Oracle. Also one can look at difference between them at Technical Comparison: ODP.NET Versus Microsoft OracleClient.
Today,LINQ support and EF Framework is available for SQL Server and not for Oracle. There has been no public information when these providers would be available for Oracle too.
In the meanwhile, one can check for Sample Entity Framework Provider for Oracle on codeplex.