Grand cavusoglu is a very nice hotel located in Cayeli, a small town 18 km south of Rize. I agree with the previous review: this is the best place to stay in Rize. It could seem far and difficult to reach, but if you need a 3-4 star hotel for a business travel there are no other accommodation with the same standard inside the city.
You can eventually opt for Dedeman (I saw the reception, the bar and the small private beach and it's nice...) but it is located 5-6 km north of Rize and there are no towns there, so you'll always have to take a taxi to go to Rize, while in Cayeli there are thousands of white private mini buses and blue (maybe public?) buses that will take you to Rize in 30-35 minutes for the small amount of 3 Turkish Lira.
There are no buses at night, this is what local people told me, but I didn't check. Don't worry about English at Grand Cavusoglu, nobody speaks English in all Rize, so try to learn some Turkish or find alternative ways to communicate!
Rooms are nice and very clean. I would put shutters or blinds, since with the 2 white curtains the light was entering the room and woke me up on the first day. The garden and the Ottoman wooden house are amazing, while the gym is small and with old equipment. Dinner and breakfast were good as well. Really enjoyed my stay in Cayeli (very nice town by the way) and Rize. Inshallah I'll come back!