Hi mdsurf. Welcome to SitePoint.
The best ecommerce solution out there is the one made by or used by the person you are asking. Everyone has his or her favorite. Each CMS you mentioned has a big learning curve, and I'm not sure I'd touch any of them without some programming know-how (but I'm a scaredy-cat).
Just so you are aware, there are lots of hosted carts out there that take the stress out of ecommerce, and I think are worth considering. Things like Shopify, Goodsie, Big Cartel, 2Checkout and many others. You don't have to worry about any of the security issues that you'll face if you host your own software. You just pay a monthly fee of some sort.
I suggest you look int those and see if they would suffice before assuming you have to take on those giants you listed.