I have just installed HikaShop yesterday, and spent all day configuring it and playing with it. I must say it's quite remarkable, it's easy to install and kind of easy to configure. There are a lot of things that must be done before achieving the results you want, but I thing it's worth it. They have a Help System on every administration page and that can be quite useful, but some things are better answered on their forum, because you can't really cover every little detail in the Help System. But no worries, because their support for the product is really good, you get an answer fast and to the point.
So I recommend this e-commerce solution because I think it's one of the best out there.