I did the Go Oahu card 4 times total between 2015 - 2018, for 7 days twice, 5 days once, and 3 days once. I find them good value if you are willing to plan ahead for everything and pre-book everything. A lot of the activities require pre-booking and lots of planning. The only bad thing is if you want to get max value, you always be on the go, go, go.... doing 2-3 activities a day. It can get quite tiresome. If you are staying only a week, I don't recommend getting more than 3 days if you decide to do it. The other times, I was in Oahu for 2 or more weeks, so 5-7 days made sense for me. Having said that, I see it's harder to getting the awesome value it once was, they seemed to raised prices quite a bit nowadays, that it's probably just fair value now, and since I done it four times already, I probably won't be doing it anymore.
Great3