Did Namco make a Soul 'Blade' PCB? Presumed that the arcade version would be Edge only.
Just to dip into this even more, the PS2 version of Tekken 5 came bundled with the Arcade version of Tekken 1, 2, 3 and Starblade on the disc itself! This gave me the opportunity to compare the PS1 versions and the Arcade originals. There are pro's and cons to both.
As has already been said, the PS1 ports are more feature filled. However, the Arcade versions do look a bit nicer. But... only a bit. It's pretty negligible tbh. But some people will care (re: Law's model in Tekken 1, for example). The biggest thing for me in the console ports is the Arranged Soundtrack. The OST's are fine, but sound a bit naff compared to how good the Arranged versions are... right across the board.
Anyway, it's kind of a moot point I suppose when discussing the Tekken series, as you can play all of them up to and including T5 + the Arcade originals, all on the one console.
As for Ehrgeiz, I always liked how the Arcade version represented a collaboration between Namco & Square.
I will say re: load times, you have nothing to worry about at all, as Namco have always had lightning loading times on PS1. Also, the PS1 versions are still dirt cheap, so why not pick them up FIRST and just decide for yourself.