That is your experience. A properly set up Hackintosh (with a custom DSDT and the proper kexts as needed) can be as reliable as a genuine Mac.
Regarding Windows machines, I've had desktops that would be used for months at a time (mostly rendering) without a restart and never crash.
A pretty good way to test for reliability is to let Prime95 and Memtest86 run for a week or so and see if it fails somewhere along the line (obviously proper cooling is a must), many consumer machines will fail this test.
You sound pretty confident in it, so here's a question from a perspective more relevant to the discussion:
Would you found a company and make your primary product hackintosh servers? Are you willing to stand behind your 'perfect' configuration and give those customers years of support?
These guys are running a real startup. A vendor with that exact promise and a failed delivery could tank them.
1. Apples EULA does not allow OSX on non-apple hardware.
2. Some major updates can break customizations and require some modifications (bootloaders, etc) to be re-installed
I have no problem helping a friend set up a Hackintosh when they want to save a few thousand dollars (I have set up a few already) with the understanding that they need to backup before doing any system updates and expect things to break after updating.
While Hackintosh's work well for personal use as long as you are somewhat techy and pick the hardware carefully, (putting aside the EULA issue) it does not make sense for anything large scale.
Regarding Windows machines, I've had desktops that would be used for months at a time (mostly rendering) without a restart and never crash.
A pretty good way to test for reliability is to let Prime95 and Memtest86 run for a week or so and see if it fails somewhere along the line (obviously proper cooling is a must), many consumer machines will fail this test.