I like that we can easily send out emails at any time without having to wait for someone else's schedule or availability - it makes our life much easier! As mentioned above there are some bugs here annd now with how long email campaigns take sometimes they will not go through unless you check your spam folder multiple times throughout their being sent (and even then if its been over 24 hours).
We use this as part of my job which requires me sending many automated messages daily so using something where i dont have too think about when is good timing etc would be great but overall very happy wile utilizing them currently!!