I have the perfect controlled experiment! I own two of my favorite Everlane silk shirt. I keep one for special occasions and only dry clean it. I wash the other by hand or delicate cycle, and line dry it.
The washed shirt definitely looks a little different - slightly faded, slightly different texture - but I'd say it's held up very well. I don't think it shrank too much.
The shirt is the sleeveless silk button-down. It's a heavy silk, almost as heavy as my favorite Equipment shirt. The Equipment shirt holds up to washing perfectly.
I also have the same situation with two copies of a thinner Uniqlo silk shirt, and for that, I can really tell the difference between the one I wash and the one I dry clean.