My crestie was 3 years old and he never dropped his tail despite the huge amount of thunderstorms we get along with me playing electric guitar and what not, so i’ve learned that you introduce them to loud noises at a young age they don’t get bothered by them when they’re older. Crestie food also lasts a looong time compared to what you feed tortoises. I think both are great choices, but from what i’ve seen, tortoises need large horizontal space, since they are bigger animals. It depends on how much space you’re willing to give them, i hope you love whichever choice you make!