We live in Dar es Salaam and went to Zanzibar for Christmas. After researching MANY hotels we chose Echo Beach. From the first enquiry Zoe (the manager) was incredibly helpful and answered any questions I had.
We were travelling with my father in law and his family and our teenage son and 20 month old toddler. Room 1 (and 1A) is ideal if you are with a baby as it is only steps away from the bar/restaurant and pool areas so we could have dinner while our toddler slept and could easily keep checking on him. They were also very accomodating about filling bottles for him and keeping them in the fridge.
The rooms are very nice with working AC and the bathrooms are excellent, with plenty of water (hot if you want). They do not turn off the electricity at any time, unlike many resorts.
The food was lovely but there was a buffet on the 26th which was mostly fish which my husband doesn't eat (note: the sides- chips, potatoes etc were not enough- one serving between 3 people and we did have to ask for more).
The pool is fantastic and deep at one end and there are plently of loungers at the pool and on the beach. The sea was a hot as a bath but the tides meant that you could only swim at certain times.
I would certainly recommend this hotel- especially to families but I imagine that some of the other rooms would be more private.