For those of you who like converting or using proxies, you probably have a number of models in your collection whose height might be considered to be "above normal". For me, I regularly use a Dragon Ogre Shaggoth from Warhammer Fantasy as a daemon prince. This has a variety of advantages and disadvantages inside the game that are tied to its height.
The obvious advantage associated with height is the line of sight it purchases. If I equip the daemon prince with doom bolt (or a similar psychic power), then this is a guy who can potentially see over the tops of buildings / scenery that shorter than average daemon princes cannot.
The other side of the coin (of course) is that others can also see him better. This means that he naturally takes more incoming fire from opponents.
But, that ties in with the other perceived, but subtle, advantage: given the height, he makes himself more of a fire magnet than other threats that I deploy on the board. I wrote a while back about daemon prince distraction techniques. By having a larger miniature for this role, I've found (anecdotally) he becomes just a fraction more of a distraction. The big imposing bulk of the daemon demands to be dealt with! That gives me time to manoeuvre in with other pieces of the puzzle to control the game.
Has anyone had any different experience with fielding tall miniatures?