Update: OVDP Now closed - utilize the Streamlined Program
OVDP, which requires an attorney's assistance, presents a substantial expense for the client. It involve filing 8 years of returns, paying tax and penalties due for all years, paying FBAR civil penalties, and paying lawyer fees for OVDP assistance.
Meanwhile the Streamlined Procedure is significantly cheaper, requires no attorney involvement and absolves client from fees and penalties.
The only occasion where OVDP  is preferred, is where the IRS has already started a civil investigation. In such case OVDP serves to keep the consequent penalties at bay.