What's the difference between SQL2008 and sql2008 R2?

First of all, from different angles,

1 if you are VS2008 then the good fit is SQL 2008 instead of SQL 2008R2.

2 If it is VS2010, it is 2008r2 to cooperate well.

3 SSRS reproting BUILDER from 2 to 3 this is what makes developing this headache, don't think 2008r2 and 2008 are

All compatible and here to tell you that they are absolutely incompatible on this issue

4 different in SSAS and SSRS on SSAS with a lot of hands and feet, specific view of Microsoft website, SSRS provide more icons

5 If you are multi-bi that suggests 2008r2 but if it's a simple database, then there's not much disagreement.

What's the difference between SQL2008 and sql2008 R2?