What is the value of the Iron Throne track?
Control of the Iron Throne grants you the decision in all (non-battle) ties, not just ties involving you.  This can be useful to try and balance other players in respect to your own position (weaken closer players, for example, or the ones with a stronger board position).

The ability to resolve ties can be quite important when bidding, which can happen in two primary places.  First, once the bid for the Iron Throne has resolved and the order is determined, the new holder of the Iron Throne now resolves ties in the bids for the Fiefdom (sword) and King's Court (raven) tracks.  This allows the holder of the Iron Throne to bid less than otherwise and still have a reasonable assurance of a decent placement.  The positioning of other houses can also be important at this point.  Second, the bidding to defeat wilding attacks: the holder of the Iron Throne determines who gets the benefits or penalties in case there is a tie for the high or low bidder.

Finally, although it is often beneficial to let others go first in order of play, it can also be beneficial to go before your opponents.  For example, your Raid order could remove another Raid order before it has the chance to remove your Support order.

All that said, while there are advantages, I usually bid harder for the King's Court track than any other, myself. I love the starred orders too much.