Opening credits: great. Music: just right for this film. Cinematography: sleazy to great effect.
Harrowing excitement in a train-wreck sort of way. This is how out of control some lives can become. "Wonderland" depicts drug-induced wildness (and its consequences) not as an aberration, but shows how it really does happen in our society. It is better than depictions of another wild group -Manson's- because all Manson films, books etc concentrate so much on Manson's insane mind rather than the overall picture of the cheap fame and randomness that is so pervasive nowadays.
If you want to see some of the best "Method-acting" on film, watch Kilmer in this movie. He shows how "The Method" can be riveting in the right role.
The filmmakers here succeed in raising "out-of-control" to the level of an art form, not just for the sake of giving us cheap thrills.