Heya,
I use a microscope called "Lady Free" and I would say it is pretty much the same thing as the Maybe Baby.
I have found it to be pretty accurate. I got mine on ebay and only paid $10 for it so maybe it is worth a look on there? Save a few $$ anyway.
I find that I have to wait at least an hour before the saliva dries enough to decipher ferning or not but I much prefer it to OPKs (no further cost involved etc.).
If you can afford the initial expense, go for it

Debbie