I did the 10-day IA with PIC back in Jan 1992. It actually took me 13 days, because the instructor dropped the FTD one day, and my electric fuel pump crunched on another day.
Overall, I was happy with the process, and have recommended PIC or fast concentrated high-retention training to anyone that asks. I flew 4 hrs of simulator every day, and 4 hours in my Arrow the rest of the day. We flew real IMC, I saw low ceilings and vis (300-2) and trace ice during training in January. One evening upon arriving back home we experienced what I thought was a carrier deck looming out of the dark mist. It was just the landing lights aside the runway, but that optical illusion has reminded me to trust the gauges over the years. I wanted to experience real wx with a competent instructor, and that's what I got.
Today, FTDs are a lot more electronic, and may be even more valuable than the old mechanical on which I learned. Also today, there are several outfits that take an extended cross-country for IMC work, which look interesting as a practical way to gain training experience.
You decide how you''ll train best, but I usually recommend getting it done as rapidly as you can afford, and then get out into the real IFR world and do your cloud busting on they way to your next objective.