Yes, it is standard 12V power. Just make sure your PSU can handle the extra wattage needed.
The other three questions is more or less answered in the same way.
A LCD screen is a LCD screen, however this comes in a different form factor and have some additional inputs.
The 19” model has a 1280*1024 panel, and have all the pros and cons of a similar “PC monitor”.
The real advantages is that the form factor (open frame etc), and the internal interface for CGA & EGA signals (that normally would require an additional converter). The latter option isn’t really any advantage if you are using a PC as the source, since then it is better to do the caling in the software I guess, so the monitor gets it native resolution.
My opinion is that there’s no real advantage that justifies the price compared to a standard PC monitor, if you are going for a MAME PC.
Maybe there the only reason would be that 4:3 monitors are hard to find these days…
But of course, this is only my humble opinion. I’m sure there are others with different opinions
