For those with a fairly small number of products without a lot of product options, this shopping cart will work very nicely. You wouldn't want to run a major storefront with it, but this extension is especially nice if you are just selling a few products on an existing Web site -- the extension doesn't get in the way.
There are several nice ideas here. For one thing, the product display is done with standard Joomla! articles; you just embed codes in the article that display the product name and price and allow adding to the cart. (Contrast this with the more common approach of dynamically building display pages.) Sure, the Simple Caddy approach is limited: for example, if you change products often you will go nuts changing the product description articles. But for a small store with a few stable products, it's really easy. And this approach allows you to do all sorts of things within the product display -- anything you can do in Joomla!
Again, there are significant limitations. The only payment option is PayPal (which does work just fine). Simple Caddy does not track payment status once it hands off an order to PayPal; if the customer fails to complete the payment, you won't know until you match up PayPal records with orders. Within products, you can have only one type of option: for clothing, you could have either size or color but not both size and color (unless you combine size and color to have choices such as "small red" and "large blue" -- not very practical in most cases).
These limitations are absolutely fatal for those who have lots of products and expect lots of orders. But for sites like mine (a non-profit that sells a few items as fund raisers a few times a year), Simple Caddy hits the mark.
By the way, we did look at Virtue Mart -- great component but much more overhead to set up and forces some changes in the way we approach dealing with our members. So don't ask whether Simple Caddy is "better" than something like Virtue Mart -- they are designed for different audiences and each is fine for its intended purpose.
We have not asked for support yet, but scanning the forum for the component shows that there is an active user base and questions are being answered quickly.
One additional note: when I tried to register for the forums on the Atlantic Intelligence Web site, the spam blocker kept rejecting my registration. I was using Firefox 3.0.3; trying the same thing in IE 7, it worked fine. Once registered, I could log on with Firefox. So if you run into that problem, maybe the IE solution will work for you.