Can anybody explain why people like UEFI?

[sir pball]

11. Pre-Intel Macs' firmware utterly spanked UEFI

Open Firmware, or OpenBoot in Sun Microsystems parlance, is a standard defining the interfaces of a computer firmware system, formerly endorsed by the Institute of Electrical and Electronics Engineers (IEEE). It originated at Sun, and has been used by Sun, Apple, IBM, and most other non-x86 PCI chipset vendors. Open Firmware allows the system to load platform-independent drivers directly from the PCI card, improving compatibility.
...
Open Firmware Forth code may be compiled into FCode, a bytecode which is independent of computer architecture details such as the instruction set and memory hierarchy. A PCI card may include a program, compiled to FCode, which runs on any Open Firmware system. In this way, it can provide platform-independent boot-time diagnostics, configuration code, and device drivers. FCode is also very compact, so that a disk driver may require only one or two kilobytes. Therefore, many of the same I/O cards can be used on Sun systems and Macintoshes that used Open Firmware. FCode implements ANS Forth and a subset of the Open Firmware library.

http://en.wikipedia.org/wiki/Open_Firmware

It went far beyond building a hardware tree and getting the bootloader running - OF is pretty much a nano-OS unto itself that runs a complete Forth interpreter. People can and have written complete albeit simple programs in it; the flexibility and management features it offers are still unmatched today. Pity Apple didn't stick with custom hardware when they made the architecture switch.