Actually, this was the system we were first considering before we stumbled upon coppermine... Actually, we found coppermine BECAUSE of Photopost. I saw some people discussing on a forum about photo posting scripts and they said that "if you have the budget, go for photopost, and if you don't, coppermine is your best bet. It has literally all the features of photopost." So I searched for coppermine, and couldn't find the page, coz greg's site was down, but i did manage to find the site cache in google, which led me to the ftp.
Anyway, now that I'm using coppermine I'm glad i didn't waste my money on photopost. Although Photopost may have many features coppermine doesn't, most of they are really not that useful anyway, and with coppermine i am more free to make custom changes to the script to fix my needs.
However, if you take a look at some of the sample sites, you'll find that they are actually not the same. I think it's the categories system that makes them so similar. but that's coz they're all based on traditional forums.