Having spent a LOT of time underneath hovering Chinooks, Pumas, and to a lesser degree Wessexes and SKs, the theoretical figures posted by TM seem about right to me. The Hughes 500 is a far smaller beast than any of those that I got under, But the downwash seemed to be like trying to walk into a 50-70mph wind. Much easier to wait with the load than try and approach it with the helo in the hover. But riskier with the strop, especially at night. The Wokka's 3 hooks made that a little entertaining too.
Unsurprisingly, the CH47 had the most, by far, but the the SK wasn't far behind it. Puma was a walk in the park compared to those two. Puma 2 with new engines and rotors - I can't see it being much different, because as the calculations show, mass of the object(s) being held aloft and area of the rotor disc(s) are the variables.
Which brings me to another point - a Bell 212 or 214, never went under either of those (do they even have hooks?), but I'd expect the downwash to be about the same even though the 214 has twice as many blades.