Though just a lowly PPL with IR, not an instructor, I disagree with Amin.
I know several folks who did the accelerated courses, mostly with PIC and I also know an instructor who worked for PIC for a number of years. The training is professional, thorough, and of the highest quality. Several examiners have told me the same thing. There is, however, no wasted time, and as pointed out a considerable amount of the training is on the sim.
However, I think such intensive training runs the risk that it doesn't sink in as well as the same information obtained over a longer period. Of course that depends on the individual. If you will fly a LOT of IFR in the days and weeks after passing the checkride, I think you'll be a competent IFR pilot within a few months. If you pass then don't fly, I think your skills will deteriorate very rapidly.
Accelerated course was not for me. But many excellent instrument pilots have been trained by PIC.