With an EFI card it's been great avoiding the boot loop and not having to do an nv_disable stuff either. It basically just works. Do the point update to OS X, reboot. Update Nvidia drivers, reboot. No drama.
But I guess I got coddled because I ran into a problem later, when upgrading from Yosemite to El Cap. After running the El Cap installer app and rebooting, the Maxwell boot loop occurs. I think, no problem, I'll boot into single user mode and add the boot arg. Except the installer boot process don't seem to have a single user mode--holding S did nothing.
Testing my bootable USB installers for ML, Mavericks, and Yosemite all showed the same thing. I can't enter single user mode to change the boot args, and so the boot loop occurs on all of them. Same thing with the Yosemite recovery partition.
So, moral of the story--if you're going to do a full OS upgrade, make sure the nv_disable boot arg is set ahead of time before you run the installer.
Also, a question. If you didn't do that ahead of time, how would you enter single user mode or otherwise set the NVRAM boot args for a booting installer?
Luckily I have a Mac Mini and OS X doesn't care which hardware it is installed on. So I moved the drive to the Mini, finished installation, and moved it back to the Pro. But I'm not sure what someone without a second Mac would do, once they were in this situation.