I have bumped up some info on Ovulation Microscopes for you, thought it may be of use.
I use mine and so far i have had no full ferning but then i have not fully ovulated yet (due to being ex depo user i am annovulating) and my first month of ovulation was induced so according to my doctor it doesnt count.
Personally i like them because you dont have to keep paying out, so long as you get the one where you can change the batteries it will last you for life and its shaped like a lipstick so its discreat!