I passed AUD and BEC with only Roger. I think FAR and REG need supplements. Ninja MCQ is awesome for REG. It helped me out a lot. I only did about half the questions for FAR from NINJA. Probably should have done more. I focused more on the Roger questions and reviewing my notes from each chapter. I'm not sure if I passed and if I didn't, I'll have to go back and take AUD again.
Roger just upgraded his IPQ software. Supposedly it includes more difficult questions now, particularly more difficult sims. The sims before the upgrade were downright awful. Not even the slightest bit representative of one you'd actually see on the exam except for maybe the cash flow chapter and possibly a couple other areas. If you can afford to dish out the money or have an employer pay for it, Gleim has great sims.
To summarize, I think it's possibly to pass with only Roger. I have a co worker who passed all 4 on the first try with just Roger. You'll have to keep in mind some of it is luck of the draw with questions you're asked. When I got an 83 on REG after failing with a 71, I didn't feel like I was way more prepared the time I passed. In retrospect, I didn't get hammered with business law topics that I didn't understand and the sims were pretty manageable. They weren't manageable at all when I got the 71. Amount of time studying depends on your schedule but I'd say you'd have to put in 20 hours per week and study at least 5 weeks, but that's just my opinion. Everybody is different. Good luck!
AUD- 71,79
BEC- 72,77
FAR- 83
REG- 63,71,83
DONE!