I've only been there 13 months but I've found the quality of previous and new hires are ridiculously high. Given the number of talented people applying every day I think Google could increase hiring by 100% with no appreciable drop in quality.
Google has a lot of imperfections addressed elsewhere in the comments here but the engineering culture is extremely strong and one of the best parts about being there. I think the overall "Googley culture" is suffering but it isn't for technical reasons.
Then again maybe I'm one of those C players who snuck in the past year.