I know there are color variations as with anything, but I've been told different stories. I've been told they are healty if they are real white with nice colored tips and but I've also been told that if they are real white it's because they are bleeched from being stressed. Do I want a more yellow/brown color or white?
I know they should be inflated and no damage to the foot etc...
Here is a picture of the one I had. It seemed pretty healthy. I lost it when I had to move it from a rock. I thought I had done a good job of moving it without hurting it but, it declined right after the move so... guess I messed it up.
I don't know of any "white" anemones for the hobby, that one would consider healthy when it is white. Many will not regain their zooxanthellae and are doomed to die, but others, under the right conditions, will turn to their tan/brown color as they recover.