Hi JustGetOwned,
Your CPU will only over-clock to it's own self limiting ceiling which varies CPU to CPU. i personally wouldn't over-clock any higher than 1.3v on the 4770k.
The h100 series are for enthusiasts who want to squeeze every last drop of CPU power whilst maintaining lower temps, than on air.
As an owner of a EVO 212 i'm very very happy with it!! to give you an idea of temps , my 4670k @ 4.3Ghz @ 1.26v = ~65deg during full stress using Prime95. Taking into consideration that our CPU's have a Tj Max (Throttle temp) of 100c we really have little to worry about.
The H100 (series) will cool your CPU better, in that it will reduce temperatures ~5 degrees - for a premium! An EVO 212 costs a mere £25 and a 4770k costs £250 - A H100i costs £85 - thats 34% of the cost of the CPU itself!
Consider this, why pay a premium for a h100/d14/d15 when your CPU can reach a great overclock on AIR and be well within the realms of safe overclocking?
Many people on this forum recommend top end CPU coolers because its what 'they' would buy and love to geek out on it. Considering that this is the first time you are overclocking your CPU, i wholeheartedly recommend the EVO 212.
If you need any help with the overclock itself, i'm more than happy to help you.
Cheers!