There is a Custom Function "Extra Mirror Delay" available on all H cameras. The options available are None, 25ms, 50ms (default), 100ms and 200ms.
This was implemented specifically for handheld photography, when slow shutter speeds are used.
Let's be clear here -- when he says "slow shutter speeds", he's talking about a 60th and 125th even. Maybe he's not, but I am.
I have experienced camera shake from Mirror Slap with the H, even on a large tripod, shooting window light, at 125th. Given, this was with the H1, but my point is: the mirror slap issue is not a small one. You can literally feel the camera lunge in your hands, when the shutter fires. Hold the grip, and test it for yourself.
I have found though, that with the CF of the H2, even at 50ms, it helps a good bit.
Still, I am very paranoid shooting available light jobs with the H2 body. Tripod always, which basically turns the camera into the mobility and spontaneity of a view camera. Not what I'd call a great design, in a photographer's hands. The Contax 645 was much better in this regard, but the Contax had a tiny, dark, viewfinder.
Sadly, again: "Advantage: Canon". Again.
With money on the table, no one wants to deliver a job with half the frames with mirror slap blur. Not in a good economy, but certainly not in a challenged economy.
Be forewarned. Call that "Hasselblad-bashing" all you want -- I choose to view it as "informing other commercial photographers, so they don't blow a job".