Between these 2 it would have to be Stella Artois.
Both are green glass, so you run into the problem of light damage resulting in skunked beer. Main difference is Stella bottles have larger labels that cover more of the glass, as well as higher 6pk cartons to shield from light. This USUALLY means Stella is less funky than Grolsch.
Besides, it's quite rare in my area to find fresh Grolsch, thanks to a distributor that doesn't actually care much about the quality and freshness of the beer they sell...
To clarify a point, a poster below said skunkiness isn't from the green bottle. I've been in this business for a long time and skunkiness most certainly is a result of green or clear glass. You can get skunked beer in a brown bottle, but it takes more work.
Skunky flavors and aromas are caused by UV rays penetrating glass, causeing riboflavin to interact with and break down the isohumulones (from the hops) in the beer. The resulting chemical molecule is called methyl mercaptan, which is one of the "ingredients" in a skunk's spray.
Green and clear bottles are only about 5% protective of UV light, while brown glass protects against roughly 98% of UV light.
The more protection on a green bottle, the less susceptible it is to skunking... which is why Stella isn't as bad, becuase of the larger amount of labeling on the bottles...