Alright, here's a review so far!
Nuked is a great as ever! It's really awesome you guys decided to make it official. It truly deserves it for it's atmosphere. I had a blast (pun non-intended) playing on this map once more. Now if you could make the westlondon map official as well...
Haven't tried "the descent" just yet, I'll update my post when I'll have!
The Stoner 63 is astonishing to say the least. I don't know if I'll ever pick up the SCAR again to be honest, except maybe for more precision and damage per shot. Don't get me wrong though, both weapons are great and offer a different kind of playstyle.
Now I'd recommend you to stick with mag-increasing skills for that one... 75 bullets seems like a lot, but it goes down very very quickly. Having 113, or even a flat 150 is way better and will quickly melt everything in your way. Plus, since it weights "only" 9 pounds, you still have enough space to carry a boomstick or deagle, which is more than enough to protect you when you eventually have to reload (it takes a while). Also worth noting is that the weapon is fairly accurate when you ADS and/or crouch, allowing for headshots which will take anything down pretty easily. I'd say the only issue I've encountered is when fighting bosses : the weapon lacks punch, but it's most obviously done on purpose. I'd say that in multiplayer that's okay, but in solo you'd better pick the SCAR back.
The spitfire revolver is kind of a mixed bag, so bear with me while I explain a few things:
-It has a very large ammo pool, it's kinda ridiculous really. It also has a high RoF. This basically means that the weapon is very effective (and arguably,better) as a spam-machine. You can quickly get rid of most mid-zeds while unloading a whole mag quickly.
-It is however, also a good "precision" weapon...for the firebug that is! It makes him better at range. It is also the best weapon to use "barbecue" with, making the gun somewhat of a "fire-and-forget" type of weapon. The weapon doesn't benefit from the "ground fire" skill, or it is very VERY unreliable with it, so I stick with Barbecue anyway if I plan to make the most out of the gun.
-Since afterburn in KF2 is not that effective, the gun makes a very poor secondary weapon for any perk other than the firebug and gunslinger (and maybe survivalist). It simply doesn't deal enough damage on impact to make it worthwhile, and the afterburn will often either take far too long to kill, or even be unsufficient to finish zeds. Really use it only with one of the perks mentionned above.
(I also have to say I believe ground fire is less OP than it was? I had far more troubles killing fleshpounds using the microwave gun... It's a bit underpowered right now, I believe something in the middle would be better!)
In the end, I believe it's great that the update brought us two very different and interesting weapons. I'd rather have that than dozens of reskins of the same gun!