It really hasn't bothered me, but then again i've been doing more print work than web lately so no pixel perfect stuff which would have been difficult. The interface seems OK, definitely seen worse and the cavas is a little bit blurry but it's hardly a show stopper (unless your doing pixel perfect stuff)
There was a lot of uproar about photoshop on retina and in my opinion it's been totally blown out of proportion.
Only thing thats annoyed me is when u copy an image from elsewhere its 2x the size... thats nothing an action to resize it to 50% didn't fix.
The bigger issue is the absolute fail of Creative Cloud, they promised so much and delivered nothing.. although it's still a good deal why promise things you can't deliver on.