I loved the gun mechanics. I sweared a lot at times for not hitting things, but ultimately the experience was better for it. It would've been worse with a perfectly honed and totally edgeless gunplay. The spread values made scopes and mods all the more important. That and the degradation mechanisms played excellently towards the overall feel of the game (of being just a nobody among nobodies, a person who's not a trained supersoldier, almost like playing a character in an RPG... almost), I never felt like I could just start carelessly popping heads (at least not until late game and the better guns and armor).
The bulletsponginess, I'll grant, was tedious at times. But the game was a shooter, so I tolerated it (just like I did with Serious Sam).
I've been rather lucky when it comes to bugs in games. I've rarely run into anything gamebreaking or outright intolerable (except a couple of times with VtMB, that I can remember offhand), not even with Bethesda games.
I didn't hate it, but I got sick and tired of having to reload saves ad-nauseum because my shots would seemingly miss even at point-blank range, but some AI would headshot me with a shotgun from 50 meters away. After digging enough, the tweak I found explained that the devs actually programmed about 20% of your fired shots to "not exist". As in, there was no bullet. It would consume ammo -- but it would never actually fire anything at the enemies. Additionally, every gun had a range at which projectiles ceased to exist. Even sniper rifles.
So, it's not only the silly amount of bullet-spread to contend with, but every 5th bullet didn't actually count, and they would all simply disappear out of the game if you exceeded their magical range...but not for the AI. Things did become much better a ways in with more advanced weapons, but I did not like the totally random results at times, even when there should have been 0% chance for error. I don't like it when games trifle with the player to create the illusion of difficulty.
The mod, however, tightened up each gun's range, scatter pattern, and power to models based on the actual firearms. Only, it did this for both the player
and the AI. Now...fights were far more deadly and very satisfying. It wasn't about rolling dice while you mashed the fire button, it was more like ArmA. It certainly wasn't like CoD or anything. Efficient movement and LoS became the key, and you won or lost by skill alone. NPCs dropped like flies, though, so I wound up returning damage values to game defaults.