The Z06 really is a beast... it's very easy to go fast in that car. Do you plan to track your car?
The only way to really know is to take a test drive. The two cars feel very different.
You're going to sacrifice the precision feel, the technology and the build quality if you go with the Z06... but you will get massive HP and TQ. What truly puts a smile on your face? The M3 is sweet and a great balance of everything. The Z06 is just insane. Insane can be fun.