Mr. Mario Meštrović showcases some pros and cons of choosing a Micro ORM framework over traditionally well known Entity Framework. Stack Overflow uses Dapper. Lets see why.

1. Micro ORM vs Entity
Framework
Mario Meštrović

2. Micro ORM
 Currently the most prominent micro ORMs that are available for use in
.NET are:
 Massive by Rob Connery
 Simple.Data by Mark Rendle
 PetaPoco by Top Ten Software
 FluentData -Micro ORM with a fluent API that makes it simple to query a
database
 Dapper by Sam Saffron

3. Massive
 Massive started life as Rob Connery playing around with the new Dynamic
datatype introduced in .NET 4.0. He explains his reasoning as:
 "I wanted to stay as close to the "metal" as I possibly could. This (to me) meant
that I didn't want to worry about Types, Tracking Containers, Contexts and so on.
What I did want to do is describe my table - and this is the only type I have
(which, ironically, is a Dynamic type)".
 So it just returns Dynamic objects
 Doesn’t support POCO-s

4. Simple.Data
Mark Rendle's Simple.Data is, in some ways, one of the grand-fathers of the new wave of
pared-down data access libraries (it inspired Massive, for example). Is it an ORM? Well, Mark
would say not. He states on his blog:
It's a database access library built on the foundations of the dynamic keyword and
components in .NET 4.0.
It's not an O/RM. It looks a bit like one, but it doesn't need objects, it doesn't need a
relational database, and it doesn't need any mapping configuration. So it's an O/RM without
the O or the R or the M. So it's just a /.
 Like Massive works with Dynamic objects
 Doesn’t support POCO-s

5. Example
Simple.Data
var db = Database.Open(); // Connection specified in config.
var user = db.Users.FindByNameAndPassword(name, password);
Massive
dynamic table = new Products(); //"dynamic" is important here -
don't use "var"!
var productsFour = table.Find(CategoryID:4,columns:"ProductName");
Seems immature!?

6. Dapper
 THE POINT:
I've recently started using their micro-ORM Dapper, and I
like it a lot. I get the performance of hand-coded SQL,
but without the tedious mapping from SqlDataReader to
my entity.

7. Dapper
 Why so fast?
 it’s fast because it uses dynamic method generation (MSIL) to
assign column values to properties
 ExpandoObjects
 Supports POCOs
 Doesn’t support sql querying, but it has it’s neat ways of mapping hand
crafted SQL queries to your POCOs

8. PetaPoco
 PetaPoco is a tiny, fast, single-file micro-ORM for .NET and Mono.
 Like Massive it’s a single file that you easily add to any project
 Unlike Massive it works with strongly typed POCO‘s
 Like Massive, it now also supports dynamic Expandos too – read more
 Like ActiveRecord, it supports a close relationship between object and database
table
 Like SubSonic, it supports generation of poco classes with T4 templates
 Like Dapper, it’s fast because it uses dynamic method generation (MSIL) to assign
column values to properties

9. FluentData (newest)
 FluentData is a Micro ORM that makes it simple to select, insert, update
and delete data in a database.
 It gives the developer the power of ADO.NET but with the convenience of
an ORM. It has a simple to use fluent API that uses SQL - the best and
most suitable language to query data, and SQL or fluent builders to insert,
update and delete data.
Fluent API for querying – ftw!

10. Demo
Try me!

11. Pros 
 Speeeeeeed!!!
 Take control of writing your own querys

12. Cons 
 LINQ (D-UH!),
 well.. this one is the most expensive so that’s the point
 object tracking,
 transaction management,
 intellisense,
 compile-time query checking
 etc.

13. Conclusion
 There is no single silver bullet
=>Use both Dapper and EntityFramework 