After experimenting with various food plot mixtures over the years, there is no doubt that deer preference varies from one farm to the next. For example, on one of my farms, the deer have used DER heavily, but have not touched it on the other farm. I have used iron clay peas in the summer with good results on one property and poor results on the other. You have to find out what the deer like to eat, and then stick with those choices. I used Austrian winter peas this year, but they did not fare well on soils that have somewhat lower soil fertility. However, DER, crimson clover, and winter oats all did well in the same plot as the peas. For this reason, I won't use the Austrian winter peas next year, since the deer utilize the other plant species just fine. It would just be a waste of money.
Also, I have come to the conclusion that a lot of the commerical food plot mixtures are not worth the money. They may work, but I can provide the same nutritional benefits by using basic mixtures I can buy locally, without spending a lot of money. For summer annual plots, I am extremely pleased with Roundup ready corn and soybeans. If the deer browse these plots too much, I will overseed them with buckwheat in the late summer to extend the life of the plots. For fall annual plots, I have narrowed it down to winter wheat/oats, crimson clover, and possibly DER. This is a cheap mixture that is easy to plant.
Also, about 60-70% of my plots are established to cool season perennials consisting of red clover, ladino clover, crimson clover, and chicory. If managed properly, these plots can be maintained for at least 4-5 years.
As BSK mentioned, the "old cheap standbys" seem to work best and they cost the least.