I looked at their pricing page and it looks like their $29 offering does have unlimited products now. I could have sworn it was much more limited about 2 years ago. I keep looking for an inexpensive shopping cart solution for a friend who owns a handmade crafts retail store and not finding a good one. Meanwhile he keeps paying $50 a month for a proprietary shopping cart and gets maybe 20 online sales a year.
I like Shopify, they are going to have customer service growing pains as they ramp up to handle customer loads, but going public means it is sink or swim time.