multi game PCB questions

[Aguraki]

Can someone explain me what are these exactly?

-is there a difference between original single PCB and these?
-is it better than MAME?
-why so cheap?
-what's wrong with these?

here's an exemple:
http://www.excellentcom.net/detail.asp? ... tid=307149

and here what is the difference of version a anb b?
can't figure out the difference of price,even if it's obvious the PCB looks different.

http://www.excellentcom.net/catalog.asp ... atid=52152

Anyone got one of these?
I always find suspicious these stuffs,are they legals?

edit:just read it's preinstalled emulator,so is it just a MAME?
and what advantage to be JAMMA?

100% confused here.

[cools]

Yes
No
Poor performance and emulation
The above should explain.

[emphatic]

I always find suspicious these stuffs,are they legals?

edit:just read it's preinstalled emulator,so is it just a MAME?
and what advantage to be JAMMA?

100% confused here.

Well, the hardware are often just a PC with a JAMMA interface, but near impossible to install any other O/S than DOS. The advantage of these boards is that you won't need to configure anything, it's just plug and play. But the disadvantages are many, the hardware isn't good enough to properly run most games and video modes aren't arcade perfect etc.

I used to have one that ran off a CF card with a Pentium II processor, so lots of the "Golden Age" games (1984-1988) ran pretty well and it was even possible to run AdvanceMAME+AdvanceMENU (after quite a bit of hacking). Typically, these boards have a simple GUI and a couple of hacked emulators (different MAME versions for different games).