At this price its definitly worth it, you get the original game with the two expansions. Do you like RPG and RTS? Spellforce combines the two genres' building you hero to suit your gameplay style, You lead your avatar on a quest to save the day (As per usual fantasy storyline)
The game starts you off easy but tends to suddenly throw you into the mix of things by the third mission. Spellforce is one of those games that becomes addictive as you delve deeper into the game.
A good buy for any adventure RTS/RPGer