About two weeks ago, I was on this site myself searching for a carriage tour of Central Park, and so many of these options seemed a bit sketchy. This was basically the only one we found with a phone number, so we went with Top Hat. Our guide, Mario, gave us his personal cell phone after a very helpful phone call, and we were texting back and forth in the hours before we met him in the park. He was incredibly responsive in the lead-up, and turned out to be fun, friendly and knowledgeable on all things Central Park during the ride.
My girlfriend and I had a wonderful & magical experience, made better by top notch customer service, friendliness and professionalism. I can't recommend the Top Hat folks enough - really great experience.