I stayed at Tempo Inn @David Mansion for three weeks and highly recommend it! I came here for a job and needed a place to stay while I looked for apartments. The place was tidy, with a friendly staff and great location. I'm not sure what the bad reviews are about, especially the ones complaining about the cleanliness and bad smells from the street.
The smells on the street were never overwhelming to me, and I don't understand how they are the hotel's fault. Actually, food smells are just a part of staying in Hong Kong. There are many great local restaurants to choose from as soon as you walk out the door of Tempo Inn. The location is excellent--steps from tasty food, Temple Street Market, and the Jordan MTR.
Your expectation for cleanliness probably depends on how much you paid for your room. I got mine at a large discount, so I don't expect 5-star hotel standards. But my room was clean when I first arrived and a staff member came in to tidy up and change towels/sheets every day. I was completely satisfied.
The staff was incredibly friendly and accommodating. The amenities are tidy--a refrigerator, microwave and drinking water dispenser. The laundry service was nice too (just drop off your laundry and it will be returned to your room--clean, folded and in a plastic bag). I would definitely recommend this hotel/hostel. I'm very grateful for the welcoming, comfortable stay I experienced throughout my first three weeks in Hong Kong.