I have been checking out both. We are trying to decide between either island or to do both in about a week. I LOVE Oahu and think that it has much to offer out two teens who have never been to HI. DH and I have been many times, to all islands, on awards trips.

Since we want to gear this trip for the teens and would like to try and do it in about a week or a little longer, I am finding in my research that Maui is much more expensive than Oahu...or am I wrong? Lodging and food seem quite a bit higher.

I think it depends on the kind of hotels or resorts you are considering, and the kind of restaurants you plan to eat in.

I know of a $100 hotel in Waikiki and a $200 condo hotel on Maui, but these are not the kind of resorts with all the amenities and activities you are seeking.

As far as food (trying to compare apples to apples), I found them pretty much the same on both islands.

Check www.biddingfortravel.com. regarding hotels. You can get cheaper hotels on Oahu, than on Maui.
Also, Oahu would probably be more fun for teenagers. It is more touristy.
In addition, if you want to get them T-Shirts, etc., there is a Crazy Shirts outlet on Oahu.