[starwest]

I'm curious about this as well, and believe I've asked a similar question in the past, but nobody has provided any hard data yet. I will add though, that any data should be taken with a grain of salt as most x-cart users have modified checkout in some way already which most likely won't match your checkout (or ours) completely. There are also many other variables, such as a sites demographics, that play a huge role in why one checkout method may possibly be better for you.

For our site, the improved error-handling of the One Page Checkout may be worth the price because I know we lose customers due to X-Carts sometimes cryptic error messages (which can only be customized so much). That said, our customers may like that checkout has 3 simple stages which are easy to walk through (or something else about our checkout) and there is really no way to know that without simply testing it out. It's a difficult question to answer - which is why I think you see so many different checkout types among even the most successful e-commerce sites.