I have a Seyco and it is a great saw with the biggest table of any of the saws, I think. It also is purchased from a company, (Seyco) that gives the best customer service and has the most knowledge about their saw... There are two things that some people do not like about it: 1. the cutting head tilts to 45° to the right, but only 30° to the left. 2. It does not have the rack and pinion type adjustment to tilt the head, you have to move it by pushing it the direction you want to tilt. And maybe there is a third, it doesn't come with the Pegas blade clamps. The ones on it are good, but not quite as nice as the Pegas.
The Jet, I have not even seen one in person, the only down side I have heard about is it is bottom feed only unless you purchase a set of Pegas clamps for it.
Whether any of these are negatives or not, is personal choice.