We stayed at the Blue Earth for six days in August, 2017 and really enjoyed our stay. The rooms are not perfect but are comfortable and most of them have a sea view.
The breakfast is very good with fresh fruits and juice, eggs and pancakes. The hotel restaurant also serves lunch and dinner for fair prices. Besides, there are several other restaurants around if you want something different.
The hotel staff is really friendly and helpful; they are always smiling and ready to help.
Be aware that they don't accept credit cards and there are no ATMs around, so make sure you get enough cash in Stone Town.
I would definitely go back and recommend the hotel to others.