I dont think it matters which for durability. For me, its about saving money, I buy the lesser price, and put the savings toward the $hipping that most places figure by total order price.
I think they're both made of polypropylene and they are remarkably similar, if not identical. I've a set of Paterson trays that I picked up used years ago and they're better than good. If I were to buy new today, I'd get the Arista brand without hesitation. They're just trays, after all. The only ones I don't like are the hard plastic ones. Bang one and it will crack.