I find that there's a special kind of super-nostalgia reserved for those books that you didn't read as a kid, but which were available to you during that age, and that you would have *liked* to read, but were unable to.
Legendz was totally that series.
I found this at the library where I'm subbing now and gave it a whirl.
The book SO doesn't hold up.
The characters are paper-thin, the art is simplistic by today's standards, and the characters are of the elementary-school-but-act-like-angsty-high-schoolers-who-do-no-homework variety. Protagonist Ken has no life outside of playing Legendz, and there's a school society of elite players, and the girl who likes him is an avid Legendz user...you get the idea. Special mention goes to the Legendz concept itself: Legendz was a Pokemon and Digimon rival in Japan, but it never grew out of infancy in the US, and the Legendz brand didn't find their own niches the way Pokemon and Digimon have these days. There's an outdated, deader-than-disco vibe to the Legendz craze in these pages.
Funny thing, though. Reading it with that ole' active-reading lens, I got why I wanted to read this so badly. The above tropes are crack to tweens. The artwork, the tropes and cliches, the total lack of character depth all *works* for that age group. Pokemon had the 'catch em all' craze, Digimon was the one with a mature plot, and apparently Legendz was just 'let's duke it out with huge creatures.' It works. It's fun. Stupid fun, but fun. ^_^
So basically, present-day-me cringed reading this, and tweenage-me was having the time of his life. And midway through, when I finally gave myself over to it, I had an overall pleasant, if not absurd read.