We have had Mercury about five weeks. He has a very sweet personality. I don't think he will change, we've had him in some kind of stressful situations (7 hour car trip with stops at truck stops for potty breaks; a picnic with about 70 people who all wanted to play with him; and a long RV trip to a weekend of auto racing with the RV parked very close to the track), and he's come through with flying colors.
Our other dog is a 13 year-old toy poodle. The puppy is a little too high energy for Oscar, so he generally tries to stay out of the way. Oscar has full run of the house and RV. The puppy probably will too, probably when he's about a year old or so. So i'm expecting the crate will be used daily for about 9 months or so.
I honestly don't know how he would feel about the more limited visibility. That is a good point! I'll have to try covering the top of the crate he's in now.
Copland, I love the story about the dogs figuring out the zipper!