Rye would get the edge over winter wheat in my book. It scavenges nutrients better....adds more biomass to the plot with its root system. However, from a logistics standpoint, rye can create more of an issue the following summer as it gets fairly tall - great for fawning cover, but can be tough to mow for guys with limited equipment. Also, I think rye continues to grow at a lower temperature than WW - which is why folks like it for early spring forage for a deer herd seeking quality forage at its most desperate time of year.
We actually started using barley in place of rye in most plots - mainly because it heads out early in the summer, providing a great food source for hen turkeys and their poults.