At first glance, the game seem similar, so what are the key differences with World of Warcraft? Are both worth acquiring together?

How lonely do I feel in this thread... Anybody got an opinion?

I assume your talking about the two WoW board games?

If so, they share some similarities in that both are about quests in a fantasy world, and players take the roles of characters in that world meeting monsters, fighting each other, and trying to fulfill various objectives. In both games, allies, objects, and quests are determined by card draw and represented by cards. However, beyond that, the game play is very different and the feel is different. In some ways WoW, in my opinion, is a more structured environment whereas Runebound can be more openended. In that sense, Runebound is really a rule set that can be applied to a number of different fantasy environments, whereas WoW is a particular fantasy envrionment to which a rule set is applied. And the rules for WoW:the Board Game are very different and much more complex than the rules for WoW:The Adventure Game. The latter is closer in simplicity to Runebound, whereas the former is a much more involved game that can take hours to play and has complex rules for combat and for developing your hero.

WoW: the Board Game is also a cooperative game in part as players are divided into teams and teams cooperate to win a race to defeat the final Boss Monster (or failing that, to kill the other team). WoW:The Adventure Game is not cooperative as each person is on his or her own and the object is to be the first player to gain fame points. There is no overarching quest as such in WoW:The Adventure Game; there's no single narrative arc as there is in WoW: the Board Game or in Runebound.

The rules for all these are posted here on the website, I believe, and reading them can give you a good feel for their similarities and difference. I suppose it would be possible to create a WoW version of Runebound by changing the heroes and the map. In that sense, as I say, Runebound is more of a fantasy game system that is very adaptable whereas WoW is a very specific fantasy world with specific characteristics.

I should have added that I play and enjoy all three games and each gives me a very different experience as a gamer. At the moment, I must admit, WoW: The Adventure Game is seeing more playtime, partly because it's newer and partly because I like the game system itself. And new character pack expansions are being created that bring even more flexibility and replayability into the game as each character has his or her own deck of ability cards, much like the character cards in Runebound.