Best ebay mass listing software?

Looking to sell a ton of items via ebay and was wondering what software from your guy's experience has had the best features and usability for mass listings? Looking for any type of solution whether it be free software or premium paid.

i have been with kyouzou for the last 7 years they are the best. Before we tried them we went through many of them. I really like there other platforms with amazon and ecommerse and i even ran my retail store with it it is a very powerful script. They are a little costly though i think it is 250 a month. We are grandfathered in at there old rates that is why i am able to still sell with them. With the slow down on ebay.

Thanks for the advice will take a look at em.