I honestly don't get the hate for some commando weapons. I'm almost the opposite. For everything below, I do all damage and speed reload increases, never larger mag.
I upgrade to the L85 (Bullpup) regularly after wave 1, and use it in auto mode, with taps. I like it quite a bit better than the varmint, feels like better damage per shot and you can do a spike unload on a husk, siren, alpha clot, to fast decap a bloat, etc. etc. The auto alone makes it feel WAY better than the Varmint...
If I join a server late, since I don't have an L85 but don't quite have enough for Stoner/SCAR, I also frequently buy the Mk.B on single fire. Once you get good with the aim on it, it has really good damage output per shot, I see it almost as good as a SCAR. The auto is pretty junky, slow and inaccurate, so I use it on single fire only though. But the single fire really "kicks" IMO.
I've been playing with Stoner exclusively, and then upgraded Stoner, but before that I used to use SCAR more frequently. SCAR+Stoner used to be my "fullly bought up" combo, and I used scar on single fire and switch to Stoner for spike/sustained unloads (scrakes, larger groups) - but since weapon upgrading came out, I tend to upgrade stoner so I can't carry SCAR, and just use stoner for literally everything. It's pretty boring TBH and the class feels dumb for it (1 gun fits all), but the efficiency with it is pretty good IMO. I don't know why people see it as a "trash cleaning" weapon. If you crouch to reduce recoil, aim down sights, and have all damage perks, you can deal with a scrake quite well, and it absolutely just demolishes everything really other than FP with great accuracy. And the mag is nice and long, just need to time your reloads well.
The power of SCAR is really single shot for me. Also I like the dot sight without zoom. SCAR headshots a lot of things in 1 shot, or 2 shots, and you can really clean up with a mag of well placed single shot headshots.
AK12 is OK, but to me it's a lesser Stoner. It tries to do the same thing - not really a "single shot" weapon, more of a "do everything on auto" but IMO it just doesn't do it as well as the Stoner.
FN FAL is not even a commando weapon, it's cross-perk from sharpshooter. And IMO, for a reason. The reason is that it's theoretically a higher damage SCAR, but I really dislike the zoomed sight. For some reason, it just makes me miss more than the SCAR in general, and I think it's designed as some kind of weird mix between M14 and Centerfire for sharpshooter. Single-shot, but zoomed in and a bit higher damage, in theory. The auto on it honestly blows. There is a lot of recoil unzoomed IMO, zoomed auto is just lol, and in either case the mag is out before you know it, you've missed 40% of your shots, and you're reloading... The sad thing is, I also don't like it as sharpshooter, because the M14 is better at what the FN FAL is trying to do IMO, and mostly I play centerfire+upgraded railgun with SS anyway. I just like that combo more than any other for SS and I feel like those weapons are the reason you play SS (IMO everything that M14 does, gunslinger does WAY better, and everything the FN FAL tries to do, a commando with SCAR or Stoner does WAY better).
IDK maybe I'm weird but I do pretty well on pubs lol.