RocknRolla, it's good. Not great, but good. It has some very funny moments, the acting is top notch and it looks pretty sweet.
However, the plot is fucking shit, the set up is given away in the first 20 seconds of the film (literally) so there is no build up to anything. You don't get a feel for any of the characters, and it is quite confusing at times. Johnny Quid is a pretty cool character, and he made the last quarter of the film worth the while.
Guy Ritchie has obviously been spending too much time in his mansion with Madonna.
My advice; Wait for the DVD and rent it. Don't bother going to the cinema.