I had to find the old literature to get the features of the different models right:
Standard and Pro Models - These have tubular rails like the Model 510, and a Model 510 type fence
Standard Model - Approx. 48" tubular rails, tie rod at end, no extension tables
Pro Model - 67" tubular rails, 2 extension tables, 2 support legs
Deluxe and Ultra Model - These have extruded Excalibur rails and an Excalibur fence
Deluxe Model - 49" extruded rails, 1 extension table
Ultra Model - 78" extruded rails, 2 extension tables, 2 support legs
The unique feature of the Sawsmiths is the sliding carriage that allows the blade to be pulled through the wood for crosscuts. It crosscuts like a radial arm saw except it's not upside down and backwards. They claim the motor develops 2 1/2 horsepower, unlikely, but it is strong and runs smooth.