It's a rather well preserved castle (for what's left of it) which is a mixture of Gothic and Renaissance (Italian) style. I would not put it at the top of your list (particularly if you choose to go to the Loire Valley just for one day) but I nevertheless recommend (if you don't mind stairs) that we go quickly inside even just for the breathtaking view from the ramparts and for the tomb of Leonardo da Vinci because that would provide you with two moments of personal fulfillment and, if I were you, I wouldn't want to miss that. But I recommend that we spend more time at the Clos-Lucé.