While you could use Redshift as a source for OLAP, most OLAP tools will have their own data store. But if you are referring to ROLAP, then it can perform well if tuned properly for the star schema. This would include BI tools like Microstrategy and Mondrian with Jaspersoft.
The main issue with Redshift is the lack of multiple sort orders on a table. Take a look at our blog post on first impressions gleaned during the preview. Disclosure: we are one of a couple of systems integrator partners for Redshift.
