If you want a more serious e-commerce solution then you should stick with WP e-Commerce. It is not hard to use and now that WP e-Commerce 3.6.6 has been released it is even easier and more powerful then ever.
Hi, I am the guy who actually built the site. Thanks for the positive comments.
artrato3 – just wondering if you know why you might have got that warning, and also how you got the warning? They are a very reputable business hosted on a reputable host, so unless there has been some sort of foul play, I am baffled by this.