Very true. Not just the weight/fuel burn of the third engine but now you have an additional 30% in MX/engine cost. I have no idea what the big boys run but I do know that on private jets those puppies run around $300-$400k a piece. Not sure what a hot section on a jet eng cost but I'm sure it's high. Regardless if I won the lotto I'd have to go with the Hawker 900EX.

Keep in mind there's more than just cost associated with two vs three. Operational performance varies. I don't know specific numbers but I saw the 900EX do a short field takeoff the other day and and it made my jaw drop.