Best kneeboard for helicopter pilots  

Exactly.  Pull the foam non-slip strips off the back of a milspec kneeboard and wear it on your right leg.  When you aren't actively writing on it or referencing it, rotate it around your leg 90 degrees to the right and it is completely out of the way of the cyclic (this obviously doesn't work well for doors off).  I have been flying this way for almost 40 years.  Even though I fly SPIFR with iPads running Foreflight I still find it easier to write stuff down the "old fashioned way" plus I have info on my kneeboard that I use that is much easier to get to there than any other other way.