Seņor Lappos,
Just today I got to do some autos to a touchdown in a 407 at 9400 FT HD, having also been at Bell just last week thus having a fresh comparasion I discovered that the main and most noticable difference was at the very end of the auto where collective wasn't as effective, other than that I couldn't feel much difference, just sharing my experience. And you are absolutely right the, 206 is very forgiving in autorotation.
Emergov,
When doing autorotations in helicopters that I am familiar with I almost never look at the IAS indicator, just look outside and you'll see how fast you're going with even more accuracy.