I prefer blinds as I do not like "fancy" things, and to me, curtains are rather fancy.
I prefer the straight clean lines of blinds.
I have double blinds in some areas due to the heat as when I was having them installed, I agonized for some time about putting curtains in as well to stop the heat. However with a block out on the back of one of the blinds, I far prefer this, as you can also have the main, heavier blind up in the day and no one can see in even though you can see out.
So, definitely blinds for me!