Part of being a business traveller is staying in hotels, just as much as flying, unless you only go on day trips. Whilst there are a number of hotel reviews in places I personally are unlikely to visit, there are reviews on hotels in places I do. Overall BT gives a good balance.
I would agree with FrequentTraveller about Tripadvisor being more leisure orientated than business. I have found that sometimes it is better to look at the Tripadvisor reviews after staying. The comments can be very subjective rather than objective. I do leave comments on Tripadvisor but always be objective.