MuseScore can be frustrating due to the bugs that you mentioned, however if you stick with it, it can certainly be used to produce nice-looking scores. As a test, I notated the first part of Marieta by Tarrega. Here is the PDF file
. I'd be glad to send you the MSC file as well, but I can't attach it here. I am proud to say that I helped implement some of the guitar-related notations in the software.
You can see that it is capable of producing barre numbers: VII---|, circled-string numbers (you must currently add a normal number fingering, hit F2, and add a circle border, although I hope to put one in the fingering palette later), and pimac fingerings (the only notation software you will find with pimac in the fingering palette!
). It is also possible to do glissando, and notate harmonics with diamond noteheads (playback is not correct, but it is something to work on). It does not have tablature support of any kind at the moment.
As for replacing the piano sound with a GM soundfont with all instruments, I direct you to the page in the manual on SoundFonts
. I can't help you with Windows specific problems (I use GNU/Linux, personally), but if you post on the forums, I'm sure you will find help.
I must mention that if you do find bugs, it would be incredibly useful for everyone if you reported the bug to the forums. The author of the program is quick to fix any bugs you may find.
Feel free to ask me about how I did anything in the Marieta example. One of my goals is to make MuseScore easy for classical guitarists to use, because I personally use it to write classical guitar scores. The great thing about being an open-source program is that I can customize it to suit my needs as a guitar-player. I feel it is almost there (circled string numbers in the Fingering palette, as well as harmonic playback are two things on my TODO list), but it's already quite usable.
I hesitate to recommend it if you become easily frustrated by bugs, but if you see the value of having a free (open-source) notation program, especially one which is amenable to guitar-notation, I hope you will try it and report any bugs you find, or offer suggestions.