Saunders and Dunco 90/x are the best. They differ in their paper stops and scales - Suanders has inch and Dunco has metric scales. The Saunders' paper stops are better if you switch paper sizes often and are more convenient to unse, IMO.
You will find Dunco easels much more often on ebay.de than Saunders. Saunders is less known in Germany and therefore cheaper to buy second hand. New ones are equally expensive.