I'm pretty sure they just moved where they require user password to the beginning of the boot process instead of right at the end. Explains why it's now just a grey screen instead of showing your blurred desktop picture.
My 2008 MBP (new SSD) is at about 20 seconds from beep to login screen. My 2010 MBP (new SSD) is at about 12. I actually counted last night before I saw this post. haha. It's on par with what it was on Mavericks. I'm just thankful we're not in the olden days of 1-2 min boot times. lol.
They screwed up the boot times for me with beta/dp versions. With 10.9 it was ~10s, now it's twice as long or even more. Not a deal breaker tho, I don't shutdown my MBA very often anyways...
Public Beta 1 the boot time was much MUCH longer. Booting up and logging in took a good 30 second on my late 2013 retina.
Public Beta 2 from the moment I press power to the login screen is incredibly fast. Probably 2-3 seconds. After that it will take about 10 seconds to login. So roughly 10-15 seconds.
Which is about the same for Mavericks.
Battery life was horrible for PB1. PB2 is much much better as well.
And in Yosemite shutting down has always been much faster compared to Mavericks.