This is probably the best restored & most visited palace in Seoul - you can only go in with a tour guide & have to wait for specific times (when we were there the English time slots were: 11:30, 1:30 and 3:30) - so make sure you check the times beforehand.
The guide is good and the tour informative (it takes about 1 hr 20 mins). The palaces most famous asset - the secret garden was a little disappointing though.