Nope, you are correct with KS and Cinema, I now have dealt with both. Cinema was nice, yes you could add as many cores as you could find, the only time that it really raised havoc was with math operations during dynamic simulations, as the math computations for different CPUs would run the random algorithms differently and result in chaotic unpredictable results . But, just run the sim on one machine, bake it and then render. I was trained never to allow simulations to run during final renders anyway, so wasn't a huge problem.
But I digress....
With cinema at my last job I had conspired every single computer in the office from my MacPro tower workhorse, 4 other edit suites, the protools room, all the way down to the front office lady's 4 core imac. At one time I think I had about 320 threads going all at once. Granted some of those computers only got through a half dozen frames over the course of the render compared to the other ones, every little bit helps.
Now I am running a NR server at my new company, and yes, its 480 per year for 32 cores. The render server is actually slower than my main workstation , but it really allows me to free up my own local machine to keep working on the next project. So, if its a througput issue, then yeah, I would seriously consider it. It all depends on your needs. The other option is to look at an outside render service. I had looked at that, but we are cranking out so many dang images, that it quickly made sense to drop the coin on the network render license in house. Plus IT is specing out a new HP Z8 machine for us too, so we might be expanding ours to 64.
For a hobbyist or small house yeah the network rendering license is a bit spendy. You really have to make use of it and make sure its actually allowing you to make more money, rather than just a "nice to have". If you weren't staying with Mac, I'd say you might be better off investing in a threadripper system, then you would have the faster machine to develop on, render in the background, and save 2 cores to start working on the next project. That's how we did it until we got the network render. Now I would have a hard time being as productive without it. But its not my money I'm spending
