Recumbents are not "hard" to climb hill, they are different then regular bicycles, require less options in muscles to use to get yourself up the hills.. no option to get "off the saddle" or "use your whole body" to climb. It may seems that you are spending more time climbing than a regular bicycle, that's why most people think recumbent are "harder" to climb.
Just like anything else, once you're used to it and get your recumbent legs and lungs built up, it makes little difference.