Currently micro64 has two different VIC II emulation modes (both are half-cycle exact): »single pixel dot clock exact«(very accurate, slow) and »dynamic pixel block-wise« (quite fast, even on slower machines). Normally you shouldn't notice any differences, except in demos with a lot of VIC II trickery. If your computer is fast enough you definitely should use the accurate mode.

micro64 is a very accurate Commodore 64 emulator. The only down side is it does not include any documentation. Through trial and error I discovered that you can access the main menu by pressing F9 and use the number keys for joystick. I also "believe" only the PAL version is emulated.