What am I missing?

[Nothingfaced]

I have updated all my machines to 10.10.

My 2012 and 2013 MBP should have all the features, but what about my 08 Macbook and 09 iMac?

I know it is missing Airplay Mirroring. What other features do I not get in these older machines?

 

[editonmac]

I don't believe you'll be getting Airdrop, handoff, or some other Bluetooth or Airplay dependent features. As far as I know, everything else should be included.