My partner and I stayed at The Heart of Harlem B&B for five nights at the end of October 2012, and in many ways we can echo the positive sentiments expressed in the other reviews. The room we stayed in was a large bedroom with an en suite bathroom situated on the ground floor of the house. The room was very comfortable - with ample lighting, full length mirrors, generous storage space, and a great bed.
The surrounding area is pleasant and the tree-lined street is very pretty, and very close to the subway.
Our only issue was the noise level from 6am/6.30am on-wards. Our bedroom was separated from the common room with partition doors, where the pool table/breakfast ingredients are located and it really felt like the other guests were in our bedroom with us - we could clearly hear their conversations. To be honest It felt a little intrusive and disrupted our sleep. If you are an early riser this may not pose too much of a problem, however unfortunately it was a big issue for us.
This place has so much going for it - the price is reasonable for NYC, the hosts were lovely, and it's the largest room we have ever stayed in - which was fabulous - but we just did not feel completely comfortable with how our bedroom and the common room is currently set-up.