So on my glitched level 50 save upon leaving goodsprings, I took all of the useful melee perks (and unstoppable force as well) as a test to see how effective melee could be against the most difficult creatures in the Mojave. I went to the gun runners, and bought Gehenna, Two-Step Goodbye, Chainsaw GRA and the Fat Man (great melee weapon) then picked up Knock-Knock from Searchlight and the Nuka Breaker and unique mantis thingie from M&Rs. Then I travelled to Quarry Junction, saved, and ran through massacring the deathclaws over and over again, to see how effective melee weapons could be, and which ones were especially powerful. I was surprised that Knock-Knock was by far the most effective. With the Mauler attack in VATS, I could instantly drop any deathclaw onto his back without getting hit. An effective system I found was to use Mauler to get the deathclaw down, then switch to Gehenna and spam RT (with Rushing Water, Slayer, 100 melee skill and 10 strength) to quickly put it down. Obviously once you have three or more on you, you'll be very lucky to win, but two advlts could be handled no problem. I did still find the Fat Man to be quite effective though, although I underestimated the Big Kid mini nukes and killed myself with it the first time.

Moving on from deathclaws, I decided to head into the abyss of level one death... And headed north of goodsprings, where I again made short work of creatures that I've been killed by a hundred times. A single mauler strike from Knock-Knock instantly obliterated each Giant Radscorpion, and Gehenna (especially with rushing water) tore through cazadores, including the entire tribal village without even being hit once.

Summary: Knock-Knock is awesome.

PS: I had light armor, with travel light and atomic! so running through searchlight was unreasonably fast, especially when sneaking (with tunnel runner).