SQL Server MVP Paul Turley has an incredibly well written piece on The State of Self-Service Reporting.
All of these apply to Dynamics GP and at I.B.I.S. we've used all of them with various clients (well, except for maybe Power View on Excel. 2013 since that technically hasn't been released yet. I'm playing with it for my next GP book).
Seriously, you need to read this.
You, Me and Dynamics GP
The premier information site for Microsoft Dynamics GP
