One thing I dislike is viewing an order. In order to see all the info in one glance, I have to create an invoice. I cannot compare shipping vs billing address easily, nor see the products, status, etc without creating the invoice.
osCommerce is great in this area...

Magento is user friendly as well.

OpenCart... well, this is what we see on 1.5.1.3. No way to see what was ordered, billing address, etc. The invoice isn't bad though.

If I were better at coding

Thoughts?