Well, I personally perfer cel much more than, the 
only time I would buy a genga is that if I can 
find the cel of that particular character, kind 
of my poorman's alternative, when I can't have 
the Mercedes, a Nissan is not bad.

However there are a few exceptions, if the genga 
is done by a famous animators, then it would 
worth more than cels, but not too many of the 
famous animator actualy do gengas.

There are not many people actually collect more 
genga than cels, maybe 1 out of every 100 cel 
collectors.