I'm finding it hard to find this info, so for reference:
Going from 500-1000 is actually better, per point, than 100-500. In fact going from 500-900 is almost exactly equal with going from 100-500, anything less than that means you gain less dodge per Dex, anything more means you gain more. After that, going from you have to go up to at least 4000 Dex before you start gaining more dodge per Dex. Dex after 4000 is better than Dex after 100.
However, unless you're just below a breakpoint, just keep in mind that the more Dex you have the better it is. --- "You're sorely underestimating the power of nostalgia goggles." - adjl http://www.smbc-comics.com/comics/20110218.gif