As far as flights, 24/26 of us on our upcoming cruise booked through Norwegian. (My son is stationed in the UK and didn't get the option, but he wishes he could have because his flights were expensive!)
I am stoked with our flights. Ok, so the flights aren't great, it's a red eye, and my 8 year old will not sleep before hand, so we'll get to the ship with him having about 4 hours of sleep that night. But he'll recover, it was one less thing for me to do, and even paying for 2/3 tickets for my family we saved $500. I watched flights obsessively and couldn't find anything remotely close. Our flights back are in the evening, so we'll have to bop around Tampa for longer than I'd like, but whatever, we'll figure it out.
My sister, with similar flights is NOT happy. She does not like a red eye, and she's on different flights than her husband. (They are traveling with five children, so have two rooms, and the different rooms have different flights on different airlines.)
So I would say if you're picky about flights, and not a "go with the flow" type person, book on your own. These aren't the flights I would have picked, but I'm fine with it.