It is a bit hard to describe the Colobus Lodge, when we arrived my heart sank, the reception was gloomy, the receptionist didn't have a pen, and the whole place looked like a 1960's motel. Once we got to our room however my spirits improved, the cottages are a good size, everything works (the shower was especially good) and the gardens OK.
We stayed two nights and we were the only customers. The waitresses were friendly, the chef seemed pleased to have someone to cook for and the food was fine.
So don't go their if you want to impress your partner but if all you need is somewhere to sleep and a bit of food this is a reasonable option and a lot cheaper than the other Arusha Hotels.
We also stayed in Rivertrees and Arusha Coffee Lodge, Colobus was $100 full board, the others were $300+ B&B. There is nothing wrong with Colobus just it is not impressive.