We eat lots and lots of elk burger. I haven't developed a beef/pork preference. Make sure that it is good/recently cut fat. Sometimes butchers have some skanky fat around, and you don't want that. I call a grocery store that does their own butchering about 8:00 in the morning, and tell them I will pick it up at noon--I get that day's fat.
Tend to run 10% by weight--a leaner mix than you mentioned. If we are doing something that could use more fat, then tend to add a little oil, or maybe an egg depending on use.
