Brooks is staying cutting edge by not changing the shoe, but giving you more color choices instead. They just released two new colors in the Beast model and one new color in the Ariel model. I am a fan of both of these shoes and have blogged about both before: https://drshoe.wordpress.com/2008/11/05/shoe-review-brooks-ariel-old-vs-new/ https://drshoe.wordpress.com/2008/01/21/shoe-review-brooks-beast/. FYI as of today, Brooks does not have all the colors available on their site, so Zappos.com is a good place to go instead.
Dr. Jenny Sanders Shoe Blog 
Hi Dr. Sanders:
Thank you again for finding me the Brooks Ariel, why that shoe was for me, and why the Adrenaline’s weren’t. This shoe is fabulous. It’s been a world of difference! I finished the half marathon today and did better than expected! See you in a couple of weeks!