If you want to expand to a great US marketplace that supports fixed price as well as dutch auctions (where the price keeps dropping), Pricefalls is a great one to try.
Pricefalls has a large category taxonomy that is very important to be mapped correctly for maximum exposure. Creating a proper Pricefalls feed can be done through using your Google Shopping feed, or their custom feed format based on a template.
Pricefalls feed optimization will play a huge part in title relevancy as it will dictate which products show up for user queries.