sorry I need to say the truth, I have installed yosemite, spent a day updating everything and it has been the best OS X since a while; I'm using a 17" Macbook pro late 2011 with 8GB and I'm upgrading to 16GB. I'm not going to update to a new macbook because never had issue with Logic pro even with 8GB.
honestly Line 6 HD pro, is a great product, I changed after years of being an extremist of valves...I used to play with Carvin QuadX amp and Marshall 9200...then I fell in love for Line 6 pod Hd pro after a trial in a store....I was tempted even to buy the Pod Hd pro X. great sounds....but guys can't accept these problems with drivers...if you want line 6 to become the standard for world musician need to invest in debugging.....
I hope they fix this issue soon