They look to be about equal. They both have a lot of shows during the season, and lots of vendors. PA has 35 acres. MD has 25 faire acres and an 85 acre parking lot. PA has it's own winery and brewery. MD is sponsored by Sam Adams and a Maryland winery. They both have attendance over 250,000. PA has more shows per day and four more stages, but MD has more food stands and vendors.
MD is listed as the second biggest faire, after Minnesota. Texas is much bigger but it's technically a theme park. Maryland and Pennsylvania are both really big on the national scale though.
Also, jousting is Maryland's state sport.
I'd love to go to other ones though; see the other shows around. I can only watch Puke and Snot so many times.