I picked up the 2010 Celebration Ale from Sierra Nevada. I figured that I should compare it to a 2009 bottle and see if there is a difference. There was a noticeable difference.
Sight: Firstly the picture says it all. The newer 2010 beer has a large white head. This stayed for a good 20 minutes before I started drinking it. The 2009 beer had a much smaller head.
Smell: The 2009 beer had a more prominent grapefruit/pine aroma from the citrus hops as well as some malty caramel sweetness.
Taste: The 2010 was instant hop bitterness as you would expect with all the citrus character in droves. It was also quite carbonated. I also got a metallic twang.
The 2009 was everything the 2010 was except more subtle and balanced with none of the metallic notes of the 2010. Also less carbonation but still lively enough.
Thoughts: Personally I liked the 2009 one a little better, just because it was well balanced. My wife preferred the 2010 which was surprising as she is not too gone on bitter beers and a 65 IBU rating is fairly hefty.
I did enjoy the 2010 edition and am glad I have a few more. I will let one age for a while, though not a full year. No doubt I will pick up more bottles of this.