Jerry's apartment always sported a Mac. But in creating a replica of Seinfeld’s apartment, Hulu used a PC. That's now been - thankfully - corrected:
Hulu has updated the apartment with a Mac Performa 200 in place of the PC. We'd like to think we played a role in that decision.
Related: Some of the Mac's that were seen in Jerry's apartment over the years - Stephen Hackett | 512 Pixels