Horrible, horrible documentation, don't even think about using this if you're a user without any WordPress knowledge and just want a easy to install and implement plugin.
After trying to make the thing work with a custom theme, I gave up. There are pretty much a lot of other better E-Cart/Commerce plugins out there that don't make you shred your hair follicles as much as this.
I'm pretty sure they made the documentation cluttered and hard to read so they can earn money through "1-on-1 Premium Support", which costs you $47 a QUESTION. Yes, that's right. ONE support question costs you $47 before your shop even sees a sale.
Online help is limited as well because nobody (except the developers) know how to use the plugin themselves.
Just because they have lots of downloads doesn't mean they're going to be good (that's what I found out, sadly).