Intel 4770k Overclocking

Both will do the Job. However, the H100 will cool a tab better at the cost of a larger rad and more fans. I myself have the H80I and it keeps my CPU fairly cool. Really it depends on the case you have and how much room you have. The price difference is only $20.00.

For example. at 4.2ghz at idle i'm below 30 degrees on quiet mode. On load between 50-55 on quiet mode and playing a CPU intensive game like BF4 I sit at 40-50 on quiet mode. So the H80I does it's job well.

You have three preset settings "Quiet - balance -performance"
 
Depending on how much do you want to OC and the vcore your cpu will require for that speed. The h100i is better ofcourse, with it i think you could reach at least 4.4-4.5 before running into temperature issues, if the cpu is capable of that oc, some can't go past 4.2, some can reach 5ghz.