The PS1 version is better (Saturn has slowdown and doesn't sound as good iirc). The Japanese PS1 Superlite 1500 edition of Strikers 1945 II is fairly cheap indeed.
Avoid the non-Japanese releases (PAL: 50hz only, US: no high-score saving, both: no tate iirc). And do NOT buy the PS2 Strikers pack, it doesn't have lo-res (ugly interlace).