We have owned both the 50 93 and the DS 1500 circulator. We first purchased a used 50 93 that was built in 1993. We used the Hitzer for 5 years before purchasing a new DS 1500 circulator which we are currently using in our first year. We burn 3 to 4 ton a year.
First, both units are built like a tank and are excellent quality. I had to rebuild the Hitzer with a new hopper ring and replaced the inner steel frame that held the bricks into position when we first purchased the Hitzer. Remember we purchased the Hitzer used so it had many years of usage. I can't say enough by the service received from Hitzer. Excellent customer support and easy to order replacement items.
So now the comparisons. Remember we are only half way into our first year using the DS Circulator so obviously nothing has gone wrong with the stove or know of its true durability. I can only assume by the other users in this form, I'll have many years of solid performance yet to come. The DS Circulator seems more air tight. Without getting into a discussion over dampers, the DS Circulator holds its temp more steadily in windy conditions. This might be different with other users and chimney styles, etc, but something I observed. Also I feel the Hitzer had more steel inside its firebox, but nothing that couldn't be replaced as I pointed out. Maybe its the style of grates, but the DS Circultor burns the coal more completely between my 12hr shakes, meaning more ash and less coal in the pan. I like the ash pan better on the DS Circulator plus I had the DS company customize a lid that I place over the ash pan. This helps when I walk in the living room with the ash pan and no longer get dust kicked up from the pan while walking. The DS Circulator has a tendency to have more puff backs after a shakedown. This was a bit scary at first but now know how to control this, thanks to this forum. Now after each shakedown I crack the door a bit until the blue flame appears. I never experienced puff backs with the Hitzer, maybe because the DS Circulator has a more airtight firebox.
Good luck! You will be pleased with your decision.