Last year, I was living with 4 roommates and had the unfortunate incident of bed bugs being brought to our apartment from a hotel after a trip. We heard about John through New York magazine and a friend's recommendation. He showed up on time and inspected the entire apartment and sure enough, found traces of their "droppings." His method and knowledge is nothing if not impeccable. After living out of bags for about 6 weeks, John gave me the high sign that everything should be fine; I never saw them again in that apartment.
Two months ago, my girlfriend and I moved into our first apartment together. When a few bites showed up on my leg and my girlfriend's back, we started to freak out. We stripped the mattress, wrapped it up twice, dried everything thoroughly on high heat, etc., but still got a couple bites. We called John immediately. He and his associate, Bobby, came over and inspected the bed, the furniture around the bed, the living room, and every room in the apartment and found nothing. He even pointed out a small bug near the bed and described it thoroughly and how it often gets mistaken for a bed bug. I was impressed.
To summarize, John was professional, knowledgeable, and friendly to boot (a pest!).