I used to use OpenX, too - but it's awfully slow and needs a lot of server resources. Also it's a lot of work if you want to add many banners. At least when I used it it totally lacked any import features, so it was dozens of clicks for every banner.
In the end I wrote my own banner rotation solution based on node.js - which doesn't come with any management interface, though - it's just using files stored in directories
What are the features you are looking for?