I like lots of guns:
Saber, Lancer, Typhoon, Spitfire, CAR, Argus, Revenant, GPR, Avenger.
Valiant, Javelin, Widow, CSR, Incisor, Viper, Mantis.
BPP, CSMG, Tempest.
Venom, Piranha, Claymore, Disciple, Katana.
Eagle, Carnifex, Arc Pistol, Phalanx.
For a lot of the other guns, I just find something on this list does the same job, better. Though, in the case of the Argus/Saber, the job is just so good that both are great. Mostly it's just charge weapons or projectile weapons I don't like much. And then with guns like the Locust (which was such a beast in ME2), I'd rather throw the gun at the enemies, since it would do more damage.
Yep, unpopular opinions abound, I know there's a few there that are particularly not liked around here. And some notable exclusions that ARE popular around here.
BONUS;
Most disliked in each category;
Adas
Indra
Hornet
Eviscerator
Supressor
Bless your little cotton socks for including the Avenger.
I haven't tried out every gun yet, so I can't truthfully make a list of favorites, but based on what I've toyed with so far:
Saber, Harrier (I have an intimate relationship with ammo crates), PPR, Typhoon, Phaeston, Revenant (my ugliest child that was dropped on the head several times at birth but I love it anyway). Still no Lancer, and I haven't touched the Valkyrie.
Paladin, Arc Pistol, Eagle, Carnifex, Scorpion. I tried the Talon exactly once and was really confused, somehow. Never touched the Phalanx.
Wraith, Claymore (Claymore Huntress all day every day), Piranha, GPS, Raider, Eviscerator, Disciple, Crusader. The Venom's okay, but mine's still at a low level.
Locust (really liked it on QFI), Tempest, BPP (beast on the TSol), Hornet. No Hurricane, and I've never used the Shuriken but I'm reasonably sure it's awful.
BW (my one true love), Widow, Mantis, CSR, Javelin, Incisor, Raptor (with autofire macro). No Valiant, though it was described to me as a lighter andless powerful BW, which sounds lame.
Conversely:
Striker (Adas is in a close second)
Suppressor (I don't have very strong opinions about other pistols not listed)
Reegar (most unpopular of opinions?)
CSMG (but **** the GSMG too)
Kishock (it's just the Graal but worse, ugh)
So in summary, I think we can all agree that the Suppressor is a piece of ****.