stuharri,
You might like to try this NASA Technical Memorandum Report :-
NASA TM-109158
Title: "Why do Airlines Want and Use Thrust Reversers? - A compilation of Airline Industry Responses to a Survey Regarding the Use of Thrust Reversers on Commercial Transport Airplanes"
Author: J.A. Yetter, NASA Langley Research Center
Date: January 1995
You can get this directly from NASA or via a university library if you have access to one.
With regard to the issue of the costs of brakes vs. thrust reversers this report states that on average thrust reverser maintenance costs are more than four times greater than the cost saving associated with brake wear assuming that thrust reverser use gives a 25% saving in brake costs.