United's Economy Plus offers 35"-36" of extra legroom to those customers paying the highest Y/C fares and Premier (25,000 miles >), Premier Executive (50,000 miles >) and 1K (100,000 miles >) flyers.
There are no additional amenities offered in Economy Plus. However, since all E.P. sections are in the front half of the Economy cabins, it's safe to say that you will have your choice of either the chicken or pasta entree. Mmmmm!