What makes this better than L4D ?
Read. The. Thread.
About that 1000 enemies waves, one of my biggest complains about this game was the fact that there was a max number of spawns at any time, it made kiting extremely easy if you knew spawning points and killed in moderation.
Kind of annoying in any game, where everyone but the sharpshooter is dead and you spend the next 8 minutes watching them kite 200 enemies and kill them one at a time so they can control the spawn rate. Really hoping that's been fixed, as we'd usually quit rounds where that was happening. The last 20 or 30 enemies? Sure. The last 250 enemies? I ain't waiting around for that.
There's a specific map I remember where this tended to happen; it was a two-level jail themed thing with the upper level consisting of a square platform running around the lower inner pit, and with walls riddled with spawnpoints. That tended to go fast because the (dozens of) enemies would all line up in the chase, they'd be continually spawning, and if the last man standing couldn't kill really quickly they got swarmed. It usually ended quickly in denser maps without a coherent circle because they'd get jumped from behind and die. Hardcore servers kill you
fast, especially if they're the sort that spawn half a dozen fleshpounds at the same time. xD
I do sort of dislike how the hardcore servers tended to force people into certain roles, though; the damage resistance was so high that basically only melee/sharpshooter/medic teams were viable, with a firebug or two to get the burned debuff on everything and kill trash. That M14 is just crazy, too; one of the night-time castle maps is dark enough that you can hold down an entire side alone with laser-dot sniping until you run out of ammo, provided you have good aim.
Whether the game is better than L4D or not is personal preference. L4D is a 'get from point A to point B' with semi-scripted events in place. You could expect to get better weapons at certain places in the levels and you knew tanks would appear in certain places, for example. KF is more of an arena where you just have to survive with a break between waves. Getting the gun you want isn't a guarantee like it is in L4D.
There are mods and/or mutators that changes KF to a "get from point A to B" survival game. It doesn't have the AI Director randomness, so things like drops are static. But it makes up for it with epic amounts of fixed spawns, to the point where you have to do fighting retreats across the map sometimes. It's very difficult.
In relation to this, something else good to try are the "escape" style zmod maps for CS:S. There are some really cool ones, and they tend to focus more on your ability to move efficiently, make difficult jumps under pressure, and make good decisions on the fly. And then there are the massively buggy slapdash vehicles that you always fall through...
Definitely agreed on spawn issues, though, I've had more than a few times where the last enemies were trapped or failed to spawn.