I did my IMC two months ago. I used the Elite simulator at my club when the weather was too bad or to practice before doing new exercises in the air. I found it very useful, and completed in 15 hours. My instructor said most people he teaches are up to standard within the 15 hours since the club has had the sim.
I've just bought a copy of Elite for myself, to keep up to speed and practice for my IR. I know two ex instructors who are now flying for the airlines who practised at home with Elite. It's not cheap at about £320, but is very good, and only 1.5 hours of Seneca time.