This film isn't bad nor great but it's certainly good and deserves at least 3/5 stars.
I personally loved Val Kilmer as Batman and would have liked to see him return. God rest his soul.
The rest of the cast is great too. Jim Carrey as Riddler is what you'd expect and Tommy Lee Jones as Two-Face is unhinged and violent.
Tim Burton co-produced Batman Forever and I think that's why the film suffers (which is something I thought I'd never say). It's too extravagant. The lighting, camera work and Gotham itself is all too much. Throw in the rather camp costumes and you have a problem.
In contrast, Batman Begins and the following two Nolan films did so well because of how much more serious they were.
In conclusion, Batman Forever is worth watching but it isn't the best Batman film you'll ever watch.