Interesting that you're rundown is the opposite of what I've recently heard.

I run a small WP group and we invited a couple of companies to come along and share their experiences in using WP for ecommerce/sales and WP e-commerce was slammed pretty hard.

WooCommerce was given a lot of praise but they, like you, agreed it was early days.

None of them had used MP but I've used it for a large project when it was very early in development and my developer hacked the core so much (we needed digital downloads) it no longer resembled the original product.

A few other carts were mentioned, none really of note. I think the point that you made about 'comfortable around code' is perfect, none of these are really for the novice.