This thing is a downright vintage computer brought up to pretty nice specs. It's a techie's project and pretty impressive, but still not worth $600 dollars.
For kicks, I got OS X 10.2, to run on my 1999-era 300 MHz ibook, 160 megs of RAM, 4 megs of video RAM, on a 3 gig hard drive. While slow, it never crashed and even got on the internet. But within a few months, many of the fancier flash driven sites just wouldn't load up on the machine. I could put a small format 256 RAM chip into it, which was not available at the time, which would bring the RAM on this maxed out machine further up to 288 MB. I thought about a larger and faster hard drive and a new higher capacity battery, but there are just too many things that would still take forever to work with in the context of OS X 10.2.
The machine pretty much works best with OS 8.6 through OS 9.2 as any version of OS X is too RAM hungry for the 300 Mhz. clamshell iBooks of 1999.