I think the biggest part of your decision has to be based on what you plan to do. how big a table do you need, what sizes of material do you expect to cut, and how strong is the machine. how are the linear bearings supported, etc. look into the prices and features and add on capabilities of each machine do you need a 4th axis, how well do the machines perform continuous motion etc.
you might also inquire into the new hd and hds series routers from techno, a robust machine, but I don't know if a 4th axis is a possibility.