I've just had a little play with RandyTab. It's certainly easy enough to load and use and a bit of fun but it doesn't allow you to save your files as MIDIs. It has some basic musical shortcomings (like not allowing dotted or tied notes) but it is probably worth every cent you don't pay for it. As a means of getting notes into a PC I believe the concept is quite exciting - after a few jazz guitar lessons I know the notes and scales on my fretboard moderately well, but I can't play a tenth as well as lotsa others who don't know any notes at all.
MM, I've tried Digital Ear.