Mrs. Fdog and I skydive a lot. We have friends that work at the drop zone(s) on Oahu. We've jumped there.
There are actually several different jumping operations on the airport. Oddly, they all seem to "get along" with a degree of civility; most closely spaced DZ's (even if in the same county) get along like oil and water. The jump ops on Oahu are so close you can reach out the window and touch the next one.
The Oahu jump ops are what we call a "tandem mill", which is to say, they are centered around taking first-timers on tandem jumps with production-line efficiency. If you are an experienced jumper, you will have a bland, unfufilling time here.
The jump ops are so focused on tandems, that when the last pre-scheduled tandem passenger has landed, they put away the gear and close up shop.
They all use similar TSO'd with exemption gear, and the Tandem Instructor programs are all essentially the same, so the product will be roughly the same for you. The most dangerous part of all this is the airplane ride, I'm sorry I'm not up on the current jump aircraft there.
The weather tends to the windy side, so the spots are often out over the ocean, and the views are undeniably spectacular.
Since this is ScubaBoard, I'll also pass on that someone on Oahu on vacation should do their jumps first during their vacation, then, hit the water. Tandem jumps exit from 13,000' or so, definitely flying after diving.
Janet and I are personal friends with the owners/manufacturers of two of the popular brands of tandem parachute assemblies, Strong and Racer, and both are well-built and tested products. The third prevelant manufacturer, Relative Workshop, makes quality stuff as well in their Vector, but the owner won't talk to us since we snubbed his offer to ditch our current gear sponsor and use his rigs.
What this all boils down to is an overall homogenous product offering. Just close your eyes and pick a name from the phone book. The DZ (jump operation) owners will claim their ops are better because of (fill in reason de jour here), but having seen all this ourselves, and jumped around the world, I feel confident in telling you they are all essentially the same product.
Hope this helps you!
All the best, James