Crystal was too formal for me. I didn't feel like getting dressed to the nines every night. The cabins are neat but a little small and that is an issue for me on an extended cruise. The tip thing on Crystal or at least thing i liked, if your on a full WC. That I imagine if you followed the suggested tipping sheet that gets really expensive for a sport thats already really expensive.
But Crystal has great ships and the sushi bar on the Serenity is simply one of the best in the world. The food is always excellent. Plus it's time for another experience for me.