Back when I had my 450 gallon, it was 6' x 4' x 30". It was also an acrylic tank so, I had to be very careful when cleaning algae off the acrylic. The combo of acrylic and the depth made that very difficult without getting wet. Due to the tank height and the stand height, I had to stand on a step stool to be able to reach the bottom of the tank and it was challenging.
That said, if you're going for a deep glass tank, today's cleaning magnets will make it much easier. However, a 36" tall tank is going to be tough to do other maintenance like moving things around on the bottom, etc.