From what I've read the key to AdvanceMame was that it was meant to output at 1:1 pixels at the exact Resolution, Refresh and all other settings required to exactly match the output of the original PCB. Regular Mame on any flavor, even with add on toolbars, registry hacks, etc.. cannot reach the same level of control.
The changes to the core Mame drawing system after ~.109 were to make output on a regular high-resolution, high or fixed 60hz refresh rate PC monitor *look* closer to the original monitor, but didn't address the core support required for output to a real CGA monitor. If you are sending to a 1920x1080 monitor, mame can play with the pixels and stretch that 320x240 image to fit that screen and simultate (not emulate) the original look as close as it can with current hardware. This requires a ton of CPU and even more video card muscle.
Therefore to take advantage of all these new features you need a beefy CPU and relatively new video card and a very high res screen. In the end you are left with an image that looks better than Mame pre 109, but doesn't help connecting to a real monitor and is still not the same.
With Advance Mame, since it is only processing the original pixel size (i.e. 320x240) and pushing it out 1:1 to the video card, you do not need super fast CPUs, you don't need windows, you don't need 1 GB memory 1Ghz cpu video cards. You can do it on a 300 mhz Pentium class CPU with a 4 meg video card with a few Mhz video chip, and it looks just like the arcade as you remember it. (This is why the pirate asian xx-in-1 boards use an old version of mame cross-compiled to their processor and can do it so cheaply, but clearly not optimized fully as one would with their own current version of AdvMame)
But of course AdvanceMame comes at a high cost. It takes forever to configure everything to be 'arcade accurate', you need to have somehardware and 16 bit operating system knowledge, and you deal with long load times since nothing is being addressed for performance that a 32 bit O/S gives you. But those are the tradeoffs.