Ally Haldir of Lórien is really only worth the cost in multi-player mode. Witness, for example, the fact that Wandering Ent has exactly the same stats but costs only half. Yes the Ent enters play exhausted, true, but it's still dirt cheap comparatively, and always a better choice. However, where Haldir shines is in sheer versatility for multiplayer. In solo, he is just way too expensive. But in multiplay, you can pile Silvan attachments on him to make him a powerhouse supportive ally for your fellow players, either tanking with sentinel or spanking with ranged. Plus the artwork is Magali at her finest, as always.

Haldir of Lorien is a pretty good (albeit much to generalized) ally. Four resources is way too expensive for two of something and three health. He also has the misfortune of having a much better hero version. Ranged and sentinel though, is probably worth it; and versatility is handy.