I love Batman Forever. I think it's hugely entertaining. Whereas Burton's movies took a lot from film noir and 30's horror movies, Schumacher's try to get closer to the feel of comics themselves. You can decry Schumacher's Batman as 'unfaithful to the comics' if you like, but only if you're naive enough to not be aware of Batman's full seventy year existence.
Forever combines the light-hearted with the darker aspects very well indeed. The Riddler is hilarious, but he's also unhinged and creepy. Dick's story arc and Batman's attempts to stop him following his path contain elements as dark as anything in Nolan and Burton's films. Bruce telling Dick, in the shadows of the Batcave, that if he follows his path, his whole life will become about revenge, and then letting him make his own choice - and Dick ultimately saving Two-Face. It's great stuff, and combines so much material from the comics to create a perfect hybrid version of Robin. At the time the film was released, everyone was surprised just how much effort went into Robin; making him a believable modern kid and someone who Batman would take with him to fight crime. He's angry, brooding and wants someone to take his pain out on. Bruce doesn't take away the pain, he just helps him harness it for a good cause. A far cry from Burt Ward.
The original Batchelor script for Batman 3 is one of the best superhero scripts ever written, make sure you find a copy. The film itself isn't as good and misses vital stuff (such as the red book and the giant bat), but Peter David's novelisation is the closest you'll get to the full version of the story.