Hi,
C|EH has a more offensive approach. It is supposed to prepare someone on thinking as an attacker and to see what options an attacker nowadays has in terms of attack vectors and tools.
CISSP is a wider field, more on the defense and management side. I remember it characterized as "wide as the sea" but "shallow". Meaning that it covers almost everything but does not get much into detail.
I highly value both. It is good to know both the offensive as well as the defensive side. Sometimes these two sides have nothing in common. So it is good to familiarize yourself with both.
I hope I helped
