rank as (something)
1. To be considered as having particular rank, designation, or characterization. The company still ranks as one of the most profitable businesses in the world. Some of it has become pretty clichéd by today's standards, but I'd say it still ranks as a fantastic horror movie in its own right.
2. To consider someone or something to have a particular rank, designation, or characterization. In this usage, a noun or pronoun is used between "rank" and "as." I'd have to rank that as one of the most thrilling experiences of my life. I still rank Tom as a great writer, even if his last book was a little underwhelming.
rank someone or something as something
to assign a particular rank to someone or something. I have to rank Sally as number one. She's the best. Mary ranked the chocolate as the best she had ever eaten.
rank as something
to have a particular rank; to serve in a particular rank. She ranks as a fine pianist in my book. Don ranks as the top economist of the day.