I've also become aware that some schools teach their students to rapidly lower collective during the slide, and I know Bell recommends you not leave the collective up during the slide, but I'm reluctant to slam the collective down - I'd rather the blades stay coned until the aircraft stops bouncing around (and I'm worried about digging the skids in if I bottom the collective too quickly). I know I'll get some people telling me I'm wrong to not immediately lower collective once you touch down.
Just back from B407 recurrent at Bell, and yes, they wanted the collective down promptly. This may minimize ground slide on their not common fine grained asphalt surface, but may introduce other complications on less benign surfaces. Most of the other training I have had has emphasized an "appropriate" rate for lowering the collective, but never slamming it down. Seems that various factors should be taken into account, including type of surface, ground speed, obstacles, etc.