My wife and I stayed at Michamvi for three nights at the end of March. The location of the resort is ideal, as it is located away from the bustle of Nungwi (which apparently turns off many tourists), and on Zanzibar's east coast. However unlike other properties on the east coast, because of Michamvi's location in Chwaka Bay, the resort faces westward. This results in some of the most spectacular sunsets you will ever see.
The beach at MIchamvi is splendid. Every day we walked for what felt like a mile down the white sandy beach. The surrounding is very organic and beautiful.
As with much of Zanzibar, Michamvi is subject to tidal extremes. Obviously, low and high tide fluctuations exist everywhere in the world. But because Zanzibar has a shallow coast and is surrounded by coral reef, the low tide pulls the ocean very far back. This was a sight to see, and an unexpected delight. Using the free reef shoes provided by the resort, my wife and I explored the low tide ocean for hours, literally feeling as though we were talking through the ocean. And when high tide returned, the clear turquoise waters return, and all is well.
The food was good - every night dinner is in a different location, and varies between buffet and a la carte service. The lunch time food at the oceanfront bar, though not included in the price, was delicious (seafood pizza and chicken curry especially).
Service was great, and the resort as a whole has a pretty laid-back vibe. The water sports station adjacent to the resort, run by the very helpful Anton, is great. Anton organized a fantastic snorkel trip for us. Use of kayaks was also free, and Anton guided us to kayak into the nearby mangroves, which was an incredible trip. All of the staff were accommodating and helpful.
Wi-fi was spotty, but I think that had more to do with the Seacom outage (a ship apparently hit an underwater cable that delivers internet to much of East Africa - sounds made up, but it's not) than with the resort.