Having worked with all ecommerce platforms I agree woocommerce is best in terms of using directly as a plugin with wordpress.

I don't necessarily agree it is the best out of the box shopping cart that can be used with wordpress however.

You could put the store in a subdirectory of the wordpress site and use any out of the box software my favorite as the most professional with tons of plugins available is either prestishop or zencart. This would provide a lot more possibilities.