CR updated its reliability data and rankings today. Sienna now gets an above average reliability rating as well as a higher road test score (84 vs 80 last year), likely due to the standard 2nd row side airbags.
Carnival, Odyssey, and Pacifica saw lower road test scores compared to last year. The vehicles are basically unchanged, I don't know what else they did to the update score other than give the Odyssey a point to for dropping the LX, thus making BSW standard.