Arcana does more damage over a short amount of time, but argent peacemaker has slightly better DPS and a slightly upgraded ability to hit switches, blocks et cetera. Arcana is definitely the more well rounded however- neither gun has a reputation for high damage and both guns are great at hitting switches, but the ability to deal short bursts of damage (and knock enemies away) makes the gun a bit more versatile.

EDIT-

The drivers are less good at hitting switches and blocks as they bounce around triggering things but have much higher damage when used correctly. When you get the ability to charge them (as in charge spam them with CTR max for guns) they'll become incredibly strong when used at a range.

If you're going to use guns as your main weapons you'll want to at least look into them. If you're using guns with swords or bombs, arcana is a decent option as you won't need to feed it damage and charge time reduction.

I would like to give some more insight to your list

___________

* Argent: easy, moderate damage, usually unsafe charge attack, very boring
This gun has very low damage per bullet in comparison with other guns but with 6 in a clip it's total DPS is fairly high. The problem is that it takes 6 clicks to empty the clip meaning you will be clicking furiously to get that high DPS. In addition to this the charge attack requires much prediction to even be viable, in fact it has moderate damage which isn't bad but the fact that it roots you to the ground longer than an Autogun charge without the immediate spread of knockback or flinch means you WILL take damage if you don't predict perfectly.

____________

* Arcana: easy, moderate damage, knockback, very boring
This gun is basically an elemental Valiance and should be able to fill nearly any need against elemental weak enemies. It's DPS is fair and it has knockback on every shot, the damage is respectable enough to make it work and the knockback keeps it so that you usually have some room to move. The charge isn't that powerful and should only really be used for it's knockback or to open up in a fight.

______________

* Polaris/Wildfire: hard to use well, moderate damage, high knockback, really a crowd-control weapon
Polaris and Wildfire are very different guns due to the single factor of the status they deal. The Polaris deals shock which makes it effective at hindering enemy movement and dealing high damage to large crowds of monsters that it shocks and herds. The problem is that the shock status can work against it by preventing it from pushing enemies away.

The Wildfire deals the same amount of damage per bullet as the Polaris but it deals fire status instead. While shock is great for taking out tight knit crowds of enemies fire deals more raw damage making the Wildfire better in situations where you can't keep the enemies all in one spot or in 1v1 scenarios. As a tradeoff for more raw damage though fire doesn't prevent the enemy from moving sometimes, for a gun that is mainly about knockback this is a good thing since you can predictable push enemies around.

The damage of these guns is fair and the charge attack should be used much like a Valiance charge, to get needed breathing room and to open up a fight.

_____________

* Nova Driver: hard to use, high damage in the hands of an expert, interesting
* Storm/Magma/Hail Drivers: like Nova, but trade some damage for status

The elemental drivers are great guns and each have their own niche. Drivers have relatively low DPS but high bullet damage this means that their uses revolve around switch shooting to bypass the small clip restriction and by using the charge "exploit" to deal high spread or single target damage.

Nova can deal massive damage on the charge and with no status you have higher DPS than other elemental drivers, however with no status you can't synergize with teammates or take advantage of monster status weaknesses.

Magma drivers are excellent guns due to the status, since it doesn't hinder movement you can make more certain predictions about enemy movement and hit them hard. You can also use the "Fire and Forget" strategy provided there are no healers and try to keep as many enemies lit on fire at a time to increase DPS.

Hail drivers have very mixed reviews but the general agreement is that they aren't as good in PVE as other drivers. The damage they deal is comparable to other status drivers but it's own mechanics often work against itself as it alchemizes up. Once it is a driver it will create ricochet bullets on every shot, each of these bullets are spawned to shoot off at random angles. The problem arises due to the mechanics of the freeze status, often a ricochet bullet will break the freeze status you inflict.

Storm drivers are the middle ground of Magma and Hail drivers. The status it deals has lower DPS than fire but it slows enemy movement like freeze. All in all a good driver but shock can make predicting enemy movement a bit tricky.

Be sure to turn off AT when using alchemer charge to get the best damage.
http://i.imgur.com/LYbzKL8.png

_______________

* Omega Tortofist: hard to use, ? damage, interesting, somewhat hard to obtain

The Tortofist is an interesting gun to have, it is almost hard to classify as a gun though. This weapon has potential to deal enough damage to compare to autoguns but it has some downsides too. This is what I would classify as a weapon that almost MUST work with another specific family of weapons to be most viable. To be more specific this weapon functions best when paired with a Sudaruska or Sealed sword line weapon. Tortofists are made to spam the charge attack the regular attack is made to push enemies into the incoming crystals of the charge attack, with a heavy sword you have a lot of control over enemies and can easily push enemies into the danger zone.

Note: The impact zone of the crystals seems to be similar to the code in the Vanaduke fight that determines where Shadow fire will fall. It will almost never fall on top of the target but with a heavy sword and some prediction you can put them there.

____________

* Overcharged Mixmaster: powerful, but very difficult to obtain

A good elemental weapon but the chances of one obtaining it is slim to nothing. I would classify this as a bit of a mix between the Arcana and a Storm Driver. It can pummel enemies with regularity like the Arcana but it lacks knockback and deals shock like the Storm Driver. The charge attack is a bit like the Arcana charge but with shock instead of knockback.

My Recommendations: For practicality I would suggest the Arcana just due to it's wide amount of uses and lack of serious drawbacks. For second place I would suggest any elemental driver except the Hail driver.

Holy-Nightmare, I mostly agree with your expansion my summary. Thanks.

I have nothing against Arcana, except that blasters are so very dull --- even on the charge attacks.

Working with tortofists starts with knowing the basic movement patterns of enemies and their reactions to bullets. Learning this takes far longer than a week but if you already have this it shouldn't be too hard, if you don't then I would steer clear of tortofists.

Part of the reason why I suggested the Arcana is that it offers you a bit of insight into many gun classes. It has the speed of an AP, power like a Magnus, and knockback like Pulsars. While it doesn't excel in these areas quite like these other guns it can provide useful information on how each type can be used.

Like how I did not go after the Gilded Griffon due to past experiences when combating the Dodgy Gremlins with the Sentenza (and later the Obsidian Carbine). Instead I went with the Callahan (pre GU), "THE CALLAHAN?!?! you ask. My reason was simple, I wanted to be able to flinch them at a distance and from what I learned with my Valiance I knew I needed something faster so after watching people play LD for a while I watched a guy messing around with a Callahan, and I noticed it's bullets were much faster than the (at the time) metagame Valiance.

Sure Blasters are boring but they are reliable and good for feeling out how you want to play the game.

I agree with bopp

@ #11
I would pick storm driver personally.