Yes, arguably the greatest conductor this country has ever had. I grew up with his performances of the Mahler symphonies on the annual Christmas Matinee in the 1970's, broadcast live on national television. Treasured memories for sure.
Some people may not be aware that the typical Philips orchestral sound in the 70's was as much the result of their own engineering priorities as of the unique characteristics of the Concertgebouw. That space has a miraculous capacity to sound glowingly warm, while at the same time illuminating every little sonic detail. Philips recordings tended to emphasize the hall's warmth, often at the expense of detail. Decca recordings with Haitink's successor Chailly from the 1980's had a different approach, less of the warmth and more of the 'pin drop' detail retrieval. The industry's switch to digital recording that happened around that time may have played a part in that as well. The Concertgebouw was perhaps one of the very few concert halls in the world that actually benefited early digital technology.
By the end of the analogue era Philips finally did nail it with the recording of the orchestral works of Debussy, partly made just prior to Haitink's departure as chief conductor. While 1977's La Mer is still overly lush and soft, 1980's Jeux and Nocturnes have that warm glow AND illuminate every musical detail, no matter how small. The difference is overwhelming. While Haitink is not generally associated with French music, to me this represents his finest hour as a conductor.
I played the whole set again today in his memory and can most 'warmly' recommend it to any music lover.