Channel Advisor is the best 3rd party software I've experienced. Slick design and easy to use. I couldn't recommend it enough!
Support response is always prompt and helpful. List your SKUs in a fraction of the time it takes on other 3rd party software listing platforms. Channel Advisor also host a number of webinars which give handy tips for success on various marketplaces.
Check your SKUs and their status in seconds, list in a few more minutes and see how quickly they go live. Reporting is also easy from CA.