I like the fact that 2:1 keeps better. 1:1 spoils easier. So if I'm making a lot of syrup ahead of time I tend to make 2:1. Yes the surface will dry and crystalize, but who cares?
I do like 1:1 in the spring. If they are taking it really well, I'll just mix it with hot tap water. If they aren't using it that quickly, I'll make five gallons of 2:1 and water it down with hot tap water when I feed it. When there is a flow, I don't bother to feed. Feeding is the leading cause of robbing. If I have a struggling hive, I'd rather steal a frame or two of honey from a strong hive to boost them than feed them and risk them getting robbed.
The other leading cause I've seen of robbing is HBH. It REALLY attracts the robbers.