I am in the very early stages of a project at http://exceptionalasp.net/ http://exceptionalasp.net/ and I am using Mongo DB for reporting data and SQL for user

I am in the very early stages of a project at http://exceptionalasp.net/ http://exceptionalasp.net/ and I am using Mongo DB for reporting data and SQL for user accounts etc. In this case the flexible schema of Mongo DB is a great fit for my data. My records have varying numbers of fields which I don't know in advance, usually include simple hierachies of data and I often need to query all this data together. Many queries that would be difficult in SQL become trivial in Mongo DB. I use SQL for data relating to user accounts, transactions etc because the SQL model fits better for critical, well defined reliable data IMHO.