Speaking from experience with both Kaiser and Dunco, their overall build quality is very similar, with similar potential faults developing over time. If I had to choose between them and a an RR Beard or even one of the better Saunders, I'd go for Beard or Saunders almost every time, unless I wanted very specific features, and wasn't going to subject it to hard use.
The Kaiser is big because of the way the mechanism is fitted - and it has a mechanical paper hold down clip (like Beard/ Kienzle), but only for one position. It can give the impression of having started as the last Leitz 24x30 4-blade easel, then been stretched to bigger sizes, with retractable posts added for smaller paper sizes.