Before the Eisenhower Tunnel was completed, Loveland Pass was one of the only ways over the Continental Divide. At times you will be driving along a sheer drop of 1000 feet or more. The payoff is that the pass is breathtakingly gorgeous. Sitting at an altitude of nearly 12,000 feet, you can look down on the valleys below. In the summer time you go hiking above treeline and take in the bizarre flora and fauna of the alpine zone. If you head up before June or July, there will likely still be massive drifts along the side of the road--some as deep as 30 feet.
Another benefit to Loveland Pass is that you can get to the resorts of A-Basin and Keystone much fast than driving all the way to Breckenridge.