FWIW, I've used this plug (as well as Redline & Toneboosters), and I've had by far the most success with Isone. Its imaging is better, the CPU load is less, and it has some very powerful features. To my ears, Ircam's effort is middle-of-the-road in terms of quality (price aside).
But honestly, none of these plugins really does the job yet. It's tricky stuff. The best binaural sim I've ever heard is Smyth Research's Realiser A8; this is so good it's spooky. But it's a standalone unit, and it costs $3K. Oh well.
I'd recommend checking out Isone in detail; I think it's as good as it gets for a human budget.