Well, he's got very few attacks in melee, so just like farseers or other shooty independent characters, he can be meleed to death. Getting to melee can be highly difficult through the rest of his enhanced army. He can also be instakilled fairly easily with his T4, though if he fortunes himself he'll be rerolling a 3+ invuln which equates to about a 87% chance to save.
The really dangerous thing about him IMO is the redeployment thing. If the eldar player uses few units, and deploys haf his army on each side of the field, he can usually redeploy everything to one side and then hit half your army with all of his. Completely screws with slow horde armies and frequently messes up shooting. Works even better when there's a big chunk of big terrain the the middle of the map.
Last edited by Culler; 03-22-08 at 08:02 PM.