Some contrasting opinions for good measure:
2008 - best atmosphere overall hands down with the Bloody Mary omnipresence and the best scare zone collection in my time attending at least. Houses were mixed - some were excellent (Scary Tales, Body Collectors, Dead Exposure, Hallow), some were weaker (Creatures, Interstellar, Disaster) and one was a relative disaster given the hype (Reflections). Streets/atmosphere/overarching theme totally dominated 08 - and were helped tremendously by the 3 additional "unofficial" zones - the mirror men, the chainsaws in San Francisco, and the zombie hoard in World Expo... eliminated a lot of dead zones.
2009 - a strong lineup of houses with great atmosphere in the park, but an overall confused identity. The Usher had fantastic park presence once you actually arrived at the event - but the lack of merchandise and diverging marketing hurt it overall. Houses were mostly great (all 3 monsters, Cleaver, SAW, Silver Screams), an average house (Chucky, though IMO it's a fantastic house) with one of the worst houses in recent history (The Spawning...) The zones were mostly blah... Apocalypse and Containment seemed to be grasping at straws, the Chainsaw zone was surprisingly ineffective/unmemorable, Cirque, while cool, was a glorified movie ad. Horrorwood and War of the Living Dead were the only two stand outs.
2010 - see, I thought this year was bad all around. The streets were mixed - Muerte was pretty but seldom scary, Zombie Gras was pretty awful, Coven hit or miss. Saws'n'Steam tended to be good, and 20 Years of Fear/Fear Revealed were fun photo op zones - but strictly that, they rarely provided real scares. Houses weren't much better. Psychoscareapy was bland, Legendary Truth was a thoughtful experiment that never really panned out, Hades hit occasionally but missed on a lot of potential. Zombie was decent, Orfanage's response was mixed (I liked it), Havoc had great actors but a piss poor presentation, Catacombs was well done but still not a knockout hit... and Hallow'd Past was pretty weak given the scope of the material they had to work with. Easily the worst offender though was the last minute nature of the icon, who failed to live up to any form of hype and never actually "scared" anyone during the event. Disappointing year IMO.