I was quite happy to read this:

Full integration of Super Orders functionality into the into Zen Cart core. Eliminate once and for all the separate Super Orders versions of the core "cousin files". Replace super_orders.php, super_invoice.php, super_packingslip.php with Super Order enhanced versions of orders.php, invoice.php, & packingslip.php.
in this post summarizing the current state of SO updating to 1.5: http://www.zen-cart.com/forum/showpo...&postcount=647

I think this is absolutely the right choice.