Comparatively speaking? I'm in favor of the current zombie spawning system over the old one on the basis of performance alone. Some blood moons killed my server. However, do I think it's good? Not really, no. There is more emphasis on searching for hidden zombies than there is on the horror factor of a zombie apocalypse. The hidden zombie/sleeper should be a thing, but if it's the only real threat, and usually by surprise or glitch, then it fails to improve the zombie mayhem. It's virtually no different than the run in and drag them out grind of old, except now instead of looking for sleeping zombies, you're looking for closets and sleeping zombies.
The other thing I've noticed is the AI is still a big problem, compounded with a number of bugs than send zombies "jumping" up the sides of walls on top of each other. It's not quite World War Z mount of zombies climbing, but rather singles leap frogging on each others heads to get to the higher levels. The spikes aren't as effective anymore and some zombies just glitch through barriers. Granted, these might be bugs, but it still hurts the games sense of purpose. Zombies are mindless and when confronted with an obstruction, they should either go around, or start bashing whatever is in front of them. Not have a zombie rave that results in zombies shimmying up the sides of buildings.
I mentioned this in another thread, but I was always partial to creating horde units that were single units, but looked like clusters of zombies. When these horde units are spawned, they'd be surrounded by a handful of single zombies to give it a more organic look and as players took out the horde units (dropped in down in health), it would start to break apart into single zombies. IE: a horde unit is "10" zombies, once the horde unit is down to 50% health, it breaks apart into 5 single zombies. I'd also make it so the horde units do significantly more damage to blocks and if a player is caught too close, would yank them in for an instant, gory mob death.
Just a thought to bring back the mob of zombies, thus a zombie apocalypse FEEL, without hitting the performance too hard.