That's kind of missing the point, the purpose isn't to really be competitive, but to have the fun and satisfaction of taking people out with nova knives and melee alone. And I think a shotgun would be more useful using similar strategies, anyway.

Two very good questions. Glad you asked.

I just quick a look at the market comparing an Ishukone Nova Knife to the Carthum Assault Scrambler Pistol and the Viziam Scrambler Pistol. Please note that these figures are not accounting for skillbooks since the attributes don't appear to change (possible bug) in the info window. For the sake of this finding due to the major design differences of both the pistol and the knife, I calculated how much damage each weapon can do in 5 seconds which seems to be a very reasonable about of time for both weapons to effective damage. After all, most close quarter combat situations tend to last only 5 seconds before someone dies.

Ishukone Nova Knife
Damage: 195 HP/hit
Charge Time: 0.5 seconds or half a second
Accounting for the amount of time it takes for the knife to discharge against an opponent before being able to recharge again: 585 HP every 5 seconds with a total of three hits. That basically widdles down half the armor of tough heavy suits in 5 seconds.

Carthum Assault Scrambler Pistol
Damage: 84 HP/shot
Clip Size: 6 rounds
Accounting for the amount of time it takes for the pistol to reload and its high rate of fire: 504 HP total with 6 six rounds fired in 5 seconds.

Viziam Scrambler Pistol
Damage: 84 HP/shot
Clip Size: 6 rounds
Accounting for the amount of time it takes for the pistol to reload and its slightly lower rate of fire: About the same as the Carthum in 5 seconds.

As you can see, the Nova Knife is actually better than the scrambler pistol in terms of damage output. Again, this is not accounting for skillbooks and this is based on situations in which two opponents are facing off against each other up close and personal where range is a moot point.

The Nova Knife has two skillbooks working for it. Nova Knife Operation which reduces the charge time by 5% per level. However, since where are talking about 0.5 seconds here, the 5% bonus is hardly noticeable. The Nova Knife Proficiency gives +3% damage per level. Here, the effect becomes much more noticeable because of the HP/hit the knife has over the pistol.

The Scrambler Pistol has more than two skillbooks working for it. But we will only focus on two. The Scrambler Pistol Operation grants +1 clip size. At level 5 you get 5 additional rounds per clip and thus dish out 11 hits. That brings the total to 924 HP in five seconds assuming you can squeeze each round within that time frame. The Scrambler Pistol Proficiency grants a bonus of +3% damage per level. However, because of the lower HP per round, the effect is not as noticeable compared to the clip size.

Let's do the math.

Nova Knife:
Damage: (((((195*1.03)1.03)1.03)1.03)1.03)=226.06 at level 5 proficiency

Pistol:
Damage: Same formula as above only replace 195 with 84 = 97.38 at level 5 proficiency

Now for more math.

Knife:
Damage: 226.06 HP multiplied by 3 hits in 5 seconds = 678.18 HP/5 sec

Pistol:
Damage: 97.38 HP multiplied by 11 hits in 5 seconds = 1071.18 HP/5sec

With the skillbooks accounted for, the pistol wins in terms of damage output as the pistol can practically widdle down almost all of an enemy merc's heavy armor in 5 seconds.

This is not accounting for the Weaponry skillbook. Even with that added, it makes no difference for the knife because the pistol will still come out on top and it's all thanks to its 5 extra rounds.