I never had problems with FFV's PS1 load times, they seemed about right to me. While I can't confirm it (google is your friend) I'm 90% sure FFVI's load times are there. Something to do with them being true 100% ports (something about being "hard coded" into the file) means that the fact it's stored on a hard drive does nothing to the load times. There's actually an option in the PSP version of the emulator to enable accelerated loading but from what I've heard it's up for the developer to enable it, and I'm sure Square Enix has no idea what it is.

So, IMO go for FFV, but don't get your hopes up for FFVI.