I'm a Croat so i've seen him play quite a few times.
well, imo he is the typical old school centre forward. strong, tall, got some pace, hard working and knows where the goal is. his weakness probably is that he aint got the best technique, so if you aplly a quick short passing game you rather leave him on the bench. but imo he will come good for the english game as it is more about tempo and power. and the striker get a few crosses. in our national team he has rather dissapointed so far but that has probably got to do more with the tactics we apply and the kind of game Croatia plays. It's more about fluid passing and we have better options in attack for our game than Nikica but he comes handy when we apply a more direct approach.
all in all, time will tell of how he has done for Everton but I hope he gets the service he needs and then I'm sure he will bang in quite a few goals.
COYB