These aren't high end water cooling, they are about as cheap as water cooling gets. Note this shouldn't be taken as a hit against either company high end water cooling is expensive, maintenance prone, and complex to install. It really isn't suited for mass production. These are the OEM (unbranded) version of popular sealed (self contained rad, pump, res, waterblock, & fluid) water cooling systems.
Kudos to both companies for ingeniously using off the shelf parts but I think you overstated the cooling challenges. Cooling something 24/7 isn't any harder than cooling it for an hour. You are going to reach equilibrium (especially with water) within minutes and if you don't have sufficient cooling the system isn't going to last an hour. If it does lat an hour it isn't going to get harder to cool over time, baring a fan or pump failure the temp after an hour, day, week, year will be roughly the same.
I've worked with the guys over at Cool IT Systems. They are a good group of people and engineers and I've used their solutions in my personal computer for low acoustic CPU cooling. When I was working with them, we had put together a PICMG 1.3 backplane and SHB into a desktop chassis running 6 GPUs. We had run a custom cooling and manifold system from 3 radiators on the chassis to cool the 2 Xeon CPUs and 6 GeForce GPUs. All this we managed to put together in a week with some help doing custom fabrication on the chassis. This would have been back in 2007/2008.
At that time, they were doing an early prototype cooling system for rackmount computing. They had essentially done the redneck setup by mounting a radiator from a Honda Accord onto the rear panel of the cabinet with a couple large fans. Was cool to see. Actually looked pretty neat too.
There may be some different staff there now as one of the guys I know has moved on, but in general, I have found them to be a very good group of people to work with and they know their stuff. They have done a lot of OEM work for other PC companies, and I believe they currently license their pre-plumbed CPU coolers under the Corsair brand.