Save the best for first: in pure sound and vision terms this is the greatest Blu-Ray produced to date. The picture quality shows sharpness, depth and contrasts above and beyond "The Dark Knight", "Casino Royale" and, in my eyes, even "Sin City". The sound quality is also in a class of its own: DTS HD Master Audio 7.1! The first BD I've come across with this quality, edging out X-Men 3's 6.1 effort for multi-channel HD class. I think most home cinema fetishists will have to buy this disc, whatever they think of the film.
The film is good, but very much an acquired taste. Contrary to many reports I had read in magazines and on the net "The Spirit" is free of bad acting, but the director has chosen and accomplished a very camp, tongue-in-cheek style for his mid 20th century heroes, and this sure as hell looks like bad acting until you size up the film's specific gravity. It is a film that takes neither itself nor the superhero genre seriously, endlessly self-parodying and always aware of the most typical cliches and how to play with them. If you just want a good superhero/comic-book flick, you may very well hate this and find it truly annoying. But if your sense of humour is generous enough you will find a lot of laughs in this film, and yet still a fair amount of the compelling and gripping; just know that the film will always let go of that grip and laugh as you fall a moment later.
As another reviewer on here states, an open mind is the key. Perhaps rent it first, if you can, it will not please everyone. But it is an entertaining and original film, think of it as a Charles Hawtrey to Sid James's "Sin City". And for anyone who lays great weight on picture and audio quality, it is a revelationary sensory experience. Great value too at the moment. Enjoy.