Well, don't let me turn you off Palawan, it's a wonderful place to visit. If you are a scuba diver, the WWII wrecks around Coron are amazing. And then of course there is the world-famous underground river. There is no reason for me to recite the list of attractions from Wikipedia, take a peek yourself.

Boracay has a nicer beach, but it's more touristy and smaller. Palawan is bigger with more to do, but a little more hassle to get around once you are there (Coron is a trip). IMHO if you want to spend a week in one place, Palawan is the better choice. If you want to do some island hopping inside a week, go with Boracay and Panglao (a tourist beach location in Bohol, they have a fast ferry from Cebu City). There are some fun things to do on Bohol, the Lobuc river cruise, the Tarsier monkeys, Chocolate Hills and you can see all those things in one day from an air conditioned tourist bus. Also some good scuba diving around Panglao.

Note that if you are staying at a resort for a few days, they will probably include transfers for free. So if you want to visit Panglao, you take the ferry to Tagbilaran and the resort you are going to will send a van to pick you up and take you to the resort. It would be sort of a hassle to manage your own transfers otherwise. So whatever resorts you stay at, ask them if they can arrange all your transfers for you.

Again just some random thoughts. If you narrow it down to a rough schedule I can recommend some resorts or activities. You should probably book your resorts and domestic flights early due to the holiday week.