There are 1st and 2nd class seats, buffet bar (except on the Beira Baixa and Alentejo lines). The Northern and Beira Baixa lines already have free Wi-Fi and this is going to be expanded to cover the entire network shortly.
Join the traveller community at the CP Window Seat on facebook.
Electic power sockets at some seats.
As an extra for your journey, the Intercidades trains have a buffet car with cafeteria service and light meals, except on the Beira Baixa line, where there are automatic vending machines (these services are not available on the Alentejo line: Lisbon/Évora/Beja).