Hello,
I've never heard of them either.
But, here are my thoughts on buying used computers through retailers:
First, I find that they charge well over market value. While not true of all dealers, many do charge as much for old iMac G3 systems as you would spend on a newer Mac Mini G4. And, that just isn't a bargain.
So, make sure you are only looking in the $100 range or less on an older iMac G3 system.
As for whether it comes with all the software pre-loaded, that is less important than whether it comes with all the original disks and manuals. If it doesn't specifically say it includes the original restore disks and manuals, then you can be pretty sure it does not.
Just having the software pre-loaded is useless. First, without the original restore disks (or at least a full retail package version of the Mac OS), then the software they install is pirated and illegal for you to use anyway. It is only valid if they include the original disks for the software that they install.
Beyond that, if it doesn't come with the original disks, then you will not be able to re-install or correct minor issues with the computer. Basically, you would be locking yourself into frustration because every minor problem would become a huge problem.
Many problems can be fixed by simply booting from the original restore disks and running a routine. Others can be fixed by re-installing. But, what are you going to do if you have a problem that requires re-installing, but you have no means to re-install. Then, you're stuck trying to patch a solution together and it just means huge frustrations for all involved.
So, look at it this way:
If they do not specifically tell you that it includes all the original media, disks, manuals, power cables, and other factory items, then don't buy it. You can safely assume that if it included these items, that they would be listed.
If you really want to work with these people, then you could call and ask them specifically if it includes those materials. But, if you don't get it in writing, it will be of little use if you find that it does not have them when it arrives.
I hope this helps.
Let us know if you have other questions.
P.S., if you'd like, go ahead and click the "Helpful" or "Solved" buttons on any of the posts / replies above if you feel they were helpful or adequately answered your question.