I have used the x-arcade encoder with an xbox.
It worked alright, but I had to modify the wiring harness since it
could not reach all of the microswitches on my cp.
Rebuilding that harness really sucked, so I wouldn't recomend it.
I also used a t.v. with an s-video connection, but the image quallity was
less than desireable, so I wouldn't recomend using a t.v. unless it has
component input and using the scanline filter in mameox.
Here is the the result.

If you plan on using a pc monitor, you may need somthing like the XCM 1080p converter
which will convert the component signal into VGA, however, if you're monitor can "sync on green"
all you have to do is hack a cable.
In the end, I wasn't satisfied with the picture quallity I was getting so I gutted it and
am now converting it into a 1-slot neo geo cab.