Which show you choose is really up to your preference and taste. Look on YouTube for videos of WOC and F! (Make sure you are looking at videos from DLR, not WDW.) See which show appeals to you and your family more. We love both shows, but would give WOC the edge for being unique to DCA/DLR. If F! is a favorite with your family, DL's version usually wins with WDW vets for being the better show. (WDW wins for having better seating.)
For WOC, look at the menus for CCR and WCT to see which is a better fit for your family. The Dining Package menus are pretty similar to the regular menus, so if you like the regular menu items, you'll probably like the package menus, too. For some people, having a full meal for the price paid for the package is a big deal. The WCT reserved area is closer to the water and the CCR area is further back (but you can request to go to the WCT area -- CMs should allow it, but YMMV). The WOC Dessert Party is the only Dining Package that provides actual chairs. You get a generous dessert plate, a bread basket, and 2 beverages. We've had very good viewing with all the Dining Packages -- it's up to your preference for food, your preference for a chair or for standing with a closer view, and your preference for time invested waiting for a good viewing spot.
For F! Dining Packages, all the reserved areas up front (HB, BB, RBT) have good-to-great viewing right up at the waterfront, so look at the menus to see which appeals most. HB is the most economical (and you can order off the regular menu, too, but will still pay the package price). BB's package comes with a souvenir cushion to sit on. All areas are ground seating. There is a premium package at RBT (first show only, reserve by phone) which includes dinner on the RBT patio while watching the show, but the view isn't as good from there as it is from the other package areas. Trade off: the premium package does have chairs. Our favorite F! package is BB, but we like HB and RBT (non-premium), too.
You will enjoy both shows, so look at the videos to get a taste of both, look over the package menus, then make your choice!