The 458 win was a great concept, but Winchester for whatever reason cut some corners. For starters, they made the case too short. The 458 Lott cured all of those ills, and then some. Lott made the case to the right length.

The 458 win mag has a bad reputation for never getting close to its published velocities. And wasn't it Jack Lott who had an almost fatal experience with the 458 win in Africa?

Also, I believe you can shoot 458 win mags in a Lott, but not vice versa.