First of all, doesn't this router require FOUR stepper motors and FOUR drivers? That makes the G540 a lot more cost competitive. You can't compare prices on a 3 axis system if you need 4 axis.
Secondly, You have a lot of area to travel. You will need all the rapid speed you can get, and just will not be happy with poor performance.
Thirdly, the MOST expensive thing you can do, is to buy something cheap now, and then have to fork out more dough to replace it later.
Get the powerful and reliable G540. Run it with a 48V PSU.