The 8" units have a 4:3 aspect ratio, and the 9" have 4:3 and 16:9... I think it is going to depend on what player I get.
I have an indian casino here-- and I have $444 worth of player's club points... So I am going to use the points to get a "FREE" DVD player. I think I will be getting a Sony 8" unit (that has 2 outputs and supports 16:9). It they have it "in stock" I will probably go with the 9" I have linked in the 1st post. If not, I would go with the "carbon fiber" 8's and save myself $60.
That listed vendor sells both kinds on eBay and has a good rating as well. It looks like they are a Hong Kong manufactuer... so I would prefer to go straight with them rather than through some "New Jersey Electronics Schlock House."
Regardless-- whatever I get is sure to keep the kiddies happy...
BTW is 4:3 and 16:9 different?! It is the same ratio after all!