I-75 is easier because it's an Interstate connecting to an Interstate, but as long as you get on northbound Telegraph (4-lane divided thoroughfare with stoplights) and don't turn right until Square Lake, you're all set. There aren't any surprises, it's just a few miles of mostly straight big road with stoplights.
Check out Yahoo maps and take a look at the two. If you're getting in late at night, 75 might be easier because you don't have to pay attention to much of anything (except the Exit 69 Big Beaver Rd. sign that you pass on the way to Pontiac).