The display itself is fine, same as any other 25" arcade monitor.
Older games are harder on bigger monitors. Especially games like Galaga and Robotron, and other ones with lots of action on screen. It is hard to watch the entire screen at once. I score about 40 percent less on the 33" Robotron (Ultracade) at Dave & Busters, as compared to the 19" one at my house (using the exact same sticks too).
But, a 25" isn't too terribly large.
Best way to decide is this.
Do you favor pre 1984 games? If so, then go for a 19" monitor.
Or do you favor post 1990 games? If so, then go for a 25" monitor.
It also depends on your cabinet. The farther away your head is from the screen, the larger you can make it.