Below are a number of blog posts with (largely) overlapping answers to the question, should I design a Tabular Model or a Multidimensional Model in SQL Server Analysis Services (SSAS)?
The posts are in no particular order.
Comparing tabular and multidimensional solutions – Microsoft product documentation for SSAS
“Tabular vs Multidimensional models for SQL Server Analysis Services” by Daniel Calbimonte at MSSQLTips
“SQL Server Analysis Services Multidimensional vs Tabular” by Mark Frawley at the Tallan blog
“SQL Server 2012: Multidimensional vs Tabular” by James Serra
“Multidimensional or Tabular” by Christian Wade
“Choosing a Tabular or Multidimensional Modeling Experience in SQL Server 2012 Analysis Services” (SQL Server 2012 product documentation)