I recently took the Sony PCM-D50 on family vacation armed with both RedHead windshield & a Rycote Portable Recorder Kit. I also own a deadkitten from Rode.
My observations are as follows:
1. Rode : Kills high frequencies as the material mesh is thick .. like the skin off a kitten.. good wind protection, but recording rain it totally destroyed the crispness of the water hitting the grass.
2. Redhead : Very impressed with these, however they are very 'snug' and so any direct wind from front caused a little rumble. No perceivable HF loss compared to deadkitten. Also they are made to fit a particular recorder, and seem to be a little loose, whipping the recorder in and out of my bag, the windshield kept coming off.
3. Rycote portable recorder kit fluffy : This was my favorite and I used it exclusively the rest of the trip. It handled most wind situations, was very transparent like the redheads, but due to it's length, the extra skin gave much better wind protection in heavier wind situations specially any direct wind towards the mics. The elastic on the fluffy was awesome, it fit very snugly onto the PCM-D50 roll cage and didn't keep coming off while drawing and stowing in my day pack.
My suggestion, fork out the $130-150 for the Rycote Portable recorder kit and get a handle, suspension and fluffy which will fit most portable recorders.