There's no point in arguing what emulators are best as each one emulates different hardware. It's like asking do you prefer NES over Amiga which is pointless.
I guess the only thing worth comparing in terms of quality/variety here is different emulator collections and/or different emulators of the same target hardware. BTW, all the links work. You need an ed2k client (like eMule to name one) to start downloading them.