With my 5s I have discovered:
1. I can set an alarm on my watch, but that doesn't get synced with Garmin connect on my phone
2. I can set an alarm on my phone, that does get synced with my watch
3. If I delete an alarm on my watch that was created on my phone, the deletion doesn't get synced back to the phone
4. If I delete an alarm on my phone, the alarm on my watch that was previously synced with gets deleted as well after sync
5. If I change an alarm on my watch that was created on my phone, the change doesn't get synced back to the phone
5. If I change an alarm on my phone, the alarm on my watch that was previously synced with gets changed as well after sync
In summary -- Alarm settings bug!