i am a student learning studio shot currently.i think to choose a tripod depends more on what you are doing.the link of the vinten tripod shows a video tripod.you can see the ball shape at the top ,that is for big cinema camera head for sony arri or red.like those made by oconnor.it can hold way heavier gear than 645df.so basically you do not need it.
and lets go back to the question.
if you travel with your camera a lot,gitzo and manfrotto is quite good enough.i only have one more recommendation that you go with metal ones.they are less expensive,and more durable.you can put it in water,on rock mountain,any where.one hit dose not compromise the whose structure.
if you do studio a lot,like i do right now.i am using manfrotto 475B.very basic studio setup.and very reliable.when you prepare for much post photoshop editing,the tripod is very steady,you will not worry about the camera is moved,and the reference is messed up.
for the head.i do not recommend ball head for MF cameras.specially if you do panoramic shooting a lot.gear head or 3 way head is better.you can see the angle you moved and you can have accurate movement.and they can be locked stronger than ball head.by the way,i am using manfrotto 229 right now.
hope this is helpful.
http://img3.douban.com/view/photo/photo/public/p1136438231.jpg