As much as i enjoyed playing Soul Calibur II it doesn't come anywhere near (for me) to the depth and skill required for Tekken 4.
Sure Soul Caliburs fighting\parrying, 8 way run system is very good and undoubtedly the best weapons based fighting game yet, it doesn't have the depth that Tekken posseses.
I've found that in SCII although you can have both blowout victories and losses, most of the time even a match between a complete n00b and an expert is pretty tight as compared to Tekken. It's maybe just me but i don't want any n00bs coming up to me and giving me a scare in a game i'm proud to play and play well (i came first in my year long university competition with a 78% winning percentage out of 249 fights).
The thing that irks me the most about Soul Calibur II is that its not a giant leap above what Soul Calibur on Dreamcast was. Sure theres walls and now they've reintroduced special weapons but what else is there? Tekken 4 on the other hand although it did introduce walls, made the movement and fighting system a little tighter (i would argue a little too tight) and added new innovative characters to the mix - e.g. Steve. In addition to this, ive never really liked the block button\dial-a-combo fighting systems, they've never really done it for me and it basically means a expert can practice for weeks on end and still get given a run for their money by someone macking the heck out of the buttons. It doesn't seem fair does it.
What drew me most to Tekken has been the sheer range of fighting styles and movements - although not entirely believable as a martial arts match it does make for a spectacular movie martial arts style fight.
It all comes down to what kind of fighting you prefer and in my case i like hand to hand combat over weapons fighting (even though weapons fighting is cool). And in this case there is no better 3D fighter than Tekken 4 (with the exception of Tag because my fave character is in there...Jun!
)