We just came home 2 weeks ago from our split trip at Turtle Bay Resort(TB) & Aulani. We spent 3 nights at TB, 6 nights at Aulani. Here are a few things that might be able to help you narrow down your choice:
1. You mentioned your city people, so for those couple days do you still want to be closer to the city? If yes, you can cross out TB because it is 45-60 mins away from Aulani/Honolulu without traffic.
2. Do you have young children? If yes, the beach at TB isn't as children friendly due to the bigger waves. The lagoon at FS/Aulani is a lot calmer and makes it more fun for younger kids.
3. If you want true relaxation for a couple days and away from the hustle & bustle, TB is no doubt your answer! FS is good too, they are like a little oasis in Ko'olina but because it's right next to Aulani, it's still a little busier. However, you can count on that 5-star FS service and get pampered! We didn't stay there, but had dinner at Noe. Even just a dinner experience, their staff deliver nothing but stellar service.
4. If you do decide to stay at TB, unless you're okay with eating at the resort for all your meals, otherwise you really need to plan out where to eat. A lot of the food trucks/restaurants up in North Shore have limited hours, so you can't just drive out and wing it otherwise you might drive around for awhile to look for food or get disappointed. Even morning coffee, unless you can drink straight espresso/Americano and you can use the ones they provide in the room, otherwise you'll be getting pretty pricey coffee at their coffee shop or you'll have to drive 10 mins out to Kahuku for better options. You need to have some kind of plans. So is that your cup of tea? Or you rather want convenience? In that case, FS will be more convenient for sure.
5. Someone mentioned TB is a very old hotel, yes it is but they completed a massive renovation last year and this resort looks brand spanking new inside! You can look up pictures/videos of the resort now, it is absolutely stunning! I can guarantee anyone walking into the TB lobby will stop, say wow and need to pick up their jaw on the floor! They did an amazing job w/ their reno, the resort feels like home to me. It is very comfortable and calm no matter which part of resort we were at. Perhaps we were there at the right timing, (1st week of December), the resort was rather quiet and I never saw more than 15-20 people at the lobby during the day and that's including the staff. It only gets busier around 5pm because everyone wants to be at the lobby/lobby bar to enjoy the sunset.
6. Do you have any credit cards that will give you extra perks for booking FS or TB? I booked our TB stay with our Amex platinum and got $150 resort credit, $30 daily breakfast credit per person, and room upgrade (there were more but those were the most beneficial to us). All rooms at TB have oceanview, just matter of standard or premium. I booked the standard so we got upgraded to premium, which is the top floor.
7. Parking @ TB - This is the one complaint I had to the resort. Not sure if it will be a deal breaker for you but I'll give my experience anyway. Self-park and valet are the same price, $35 per day for resort guests. We prefer self-park just because it's more convenient. TB parking lot is big but not when they allow beach goers to park there, FOR FREE!! This really irked me on our 2nd day when we came back from Haleiwa and we had to circle the lot 4x to finally find a parking spot. Yes, we could just roll up to valet, but again, we like the convenience of coming and going without waiting for our car. If you don't mind doing valet, this won't be an issue at all.
8. Resort fees - TB charges $49 per day, yes that's on top of the $35 parking fee, quite steep!!! I wish they could include the parking in their resort fees. That's the most I've ever paid at any resorts. FS doesn't charge resort fees. but I think their parking is valet only.
Honestly, all 3 are great options. Sorry my 2 cents went on forever!!
Hope they can help you narrow down a great stay! Happy vacation planning!