Most versions of ePSXe should be fine. As long as load times aren't faster than PS2 FDS (the fastest console version) you should be fine. I'd recommend using an emu that allows you to do the disc eject stuff, as it saves ~1 min in 100%, ~4 mins in All Levels, and ~12 mins in Any%.

RoHiSakk and Sky both run on emu, so they will know more than I do.

Also, if you plan on running on a PS emu, make sure you choose "No" for FDS, since the emu is a PS1 emu and not a PS2 emu, meaning it does not have FDS capabilities.