We just completed a 1-week stay at Zanziblue and had a wonderful time! The house was perfect for our family-group of 8 people. The beach-access was wonderful, the beds were comfortable, and we loved having air-conditioning in the bedrooms! My son loved sleeping upstairs in the open-air "loft".
A couple of other notes... The owner, Cristina, was great to work with and very responsive. The house has easy policies -- just be respectful and treat it like your house. Like, there's a stocked drink-cooler and we enjoyed the policy of simply paying for the drinks, at cost, at the end of the week.
And finally, the staff was incredible. The house manager, Bahati, was always so helpful and pleasant. And the chef, Khusein, made the best food! Breakfast comes with the rental (which you can make yourself, or have the chef prepare it). We also had the chef make dinner on most nights (for a reasonable additional cost), and it was incredible! We highly recommend it!
My only nitpick was that the wifi was a bit flaky. But I tried the wifi at several places in Zanzibar and it was flaky everywhere -- nobody had good wifi, so I can't fault the house for that.
So, the house was great, and made our vacation in Zanzibar a wonderful, memorable time!