Armored Core Nexus

Just read a review on NTSC-UK which reminded me off the first PS2 outing, I think I got a demo disc with that and Z.O.E and the later just seemed so much more faster and had better visuals so I ignored AC. But I've catched up a bit on the series and there's a lot of praise going for it so I've decided to check it out.

Which game should I start with or maybe the question should be which one is should avoid? Is it hard to comprehend without japanese language skills (Pal is a no no since I would probably be stuck with big borders and 50hz)?