I bought it for PS2 and created Manny Pacquiao (featherweight).
I am ranked around 12, and the fighters are starting to pose a real challenge.
One recommendation I will strongly encourage is to try Control Scheme #3. It re-assigns punching to the face buttons and gives much more control over the punches you throw. I found the TotalControl punching to be clunky and hard to throw hooks (particulary low hooks) on a consistent basis. Control Scheme #3 fixed all that.
The high ranked (poor) fighters can be mildly annoying as they tend to run around the ring a lot, but they are easy, and once you start raising in rank, the competetion level gets tougher appropriately.
Also, you are able to create 10 created fighters.. And they are temporarily stored for Career play.
So you can create 9 real fighters (Tyson, Foreman, Pacquiao, etc.) and then start your career. They will then be assigned random records and an appropriate rank, and you will be able to fight them instead of randomly created "scrubs." It's a nice feature, if you are willing to take time to create a few other real boxers prior to jumping into career mode.
A user at another forum took the time to post a comprenhensive list of Created Fighters, than can be accessed
HERE.
In order to access the list, you just need to join the group (don't subscribe to email, no need), and "View Messages." The Created Fighters and their attributes will be listed there.
Take care.