Which ShoppingCart to use for CPA + Affiliate Traffic?

I currently use Premium Web Cart for my shopping cart and affiliate tracking - although I think I may need to move on as the statistics and reporting is not really what I'm looking for.

I'm going to start running CPA traffic in a few days and have running aff. traffic for the past few weeks, and while things are working and I'm making money - the reporting in my opinion is severely lacking..

I'm not sure if I'm jaded because over the past 5 years I've been using Clickbank, Clicksure, RevenueWire, etc to sell my products and other peoples - but on those networks - I was always able to see a detailed report on the website with sales, refunds, conversion rates, EPC, gross sales amount, net sales, etc.

On PWC I am only able to see sale amounts, conversion rate, clicks and EPC.

In short, it's leaving much to be desired and we need aff tracking that will give us excellent stats, and a shopping cart that we can control the design on and really customize, plus pull our leads off of and that integrates with GetResponse/Aweber via an API feed.

It's just lot easier and a lot more profitable for my company if we're tracking the stats as accurately as possible.

Does anyone know if BigCommerce, Shopify or any of the other shoppingcarts out there offer detailed tracking as far as sales, refunds, gross and net sales, refunds before and after for affiliates, etc. ?

Any help would be greatly appreciated and thank you so much!!