ok first off, both games have their strenths and weaknesses and both games are far from perfect. Having said that here is my simple review comparing and contrasting the 2 games on xbox.
Graphics-Espn basketball excells the most in this category. The faces are almost perfect and you can recognize almost everyone just by their face and when they do their cut scenes, it's like watching a real game especially using your hdtv on 720p which only espn basketball has. In the face department on live they players look way to cartoony and u can barely tell anyone apart except for iverson who has a lot of tatoos and cornrolls so that makes it easy. Now on the skin textures it's about even, both aren't that great and look kinda fake, but since espn's players actually sweat and it shows, i give the edge to them.
Overall winner on graphics=espn basketball
Presentation-now this category is really close because both have a farely good presentation. Espn has the tv style presentation but with awful commentating that gets repetetive, and live has awesome commentary, but doesn't have the tv style presentation.
so overall winner is=a tie
camera angles-now this is where nba live pretty much whoops up on espn basketball. espn has about 5 camera angles but u can't adjust them or zoom in at all and u can on live.
so overall winner is=nba live 2004
Gameplay-this category is a matter of preference to most people. There are a lot of good and bad things about both games in this category, but overall I think this is where nba live improved the most over last years game. Especially when u double team people and all the plays nba live has compared to espn.
So overall winner is=nba live 2004
lasting appeal-in this category both have dynasties and both have a lot of things that will keep you playing for a long time. But since espn basketball has the 24/7 feature(which is almost like having 2 games in 1)that u can spend hours on training your player and unlocking things and it never gets boring. I would have to give the edge to espn basketball
so overall winner=espn basketball
closing comments-so bascially that puts both games at a tie and usually what breaks the tie is user preference. Meaning if you there is a certian game that you liked better last year, you'll probably like the new version better than the other game again this year too. For me it's espn basketball just because i'm a huge graphics fan and the player models are unreal in epsn basketball, but i'm sure by the end of the year, i'll have played both games the exact amount of time give or take a few minutes

That's why so far 95% of all the reviews gave espn basketball the edge this year in their reviews because of the graphics and how much more fun that makes playing the game.