MrsEB – for sure it will be a wonderful experience for you to actually see this unique piece of art. Ofcourse you want to see also van Eyck’s Virgin and Child with Canon Van Der Paele in the Groeninge Museum in Bruges, just an half hour from Ghent by train.
I think too that the Ghent Altarpiece is an absolute master work. Maybe from a distance it looks a bit like one of the better medieval or Renaissance paintings, but learning more and more Jan van Eyck had an incredible sense for detail as for instance botanical specialists have determined over 50 different species / types of plants. Seen that the panels are not that big, he must have painted those plants with really painstaking precision. During the recently finished restauration of the backpanels the specialists discovered he even painted a spider web in one of the statue niches.
The front panels are now under restoration and guess the specialists will find more interesting details once the original layers become more and more uncovered. Looking forward......
Edit: “Maybe from a distance it looks a bit like one of the better medieval or Renaissance paintings” Unlucky use of words, I mean that it stands out in comparison to other works of art at that time. In that period paintings were usually not so lively as those of later periods, but nevertheless it is mindblowing. To my opinion Jan van Eyck was way ahead of his time. It is not easy to compare artists of different periods with each other, but I think he deserves his place among all those other famous artists and do not get to my opinion the attention that actually does justice to him.
Btw, in the Caermersklooster in Ghent there are interesting exhibitions to see related to the Altarpiece. http://www.caermersklooster.be/en