I've been to a couple of games at Fenway and did the stadium tour at Wrigley (I also did the tour at Fenway). I loved both experiences - but I enjoy the history side of the game.
It's certainly different than modern stadiums. I do expect that when they eventually replace both, it will be good for the team/city, but I think we should enjoy the history while we have it.
I've also been to new Yankee stadium. Saw a game there and did the tour. Overall, I wasn't impressed. I wish I got to see the OG Yankee stadium myself. The modern version isn't very memorable like Fenway/Wrigley were. I almost forgot I've been there at times, with stadiums like Camden and PNC being miles ahead. Perhaps new Yankee Stadium is a good reminder that newer may not mean better...