I like that it has options to secure my domains for free, so if something goes wrong their are still solutions available! Also i have never been asked any questions about security or anything of this nature (which may be due to me not having used them enough yet).
So far nothing at all which makes sense because they seem very reputable as well!! The best part would probably being able to get multiple emails per day sent out from your gandi account without you needing too do much work yourself other than confirm each email address once its added into one of yours accounts via an automated process - no need really but just nice feature :).