That is a good question, really.
When I picked up the cab, I had every intention of turning it into a MAME cab. When I got it home and started going through it was when I decided to restore it. There was 3 major things that made me decide to restore it back to a Centipede in lieu of MAME'ing it:
1. The cab wasn't really in that bad of shape other than the water damage to the two panels. Even if I were to MAME the cab, I was going to have to fix that anyway, so that wasn't a factor. Most of the original parts and pieces were intact; the marquee retainers, most of the original harness, power supply & ARII board (no sound, though), cp (hacked, but fixable). The monitor board hadn't been hacked up by someone converting it to a horizontal game, and the original light fixture & speaker board were just fine. Also I had an original 2.25" Atari trackball & volcano buttons just sitting on a shelf. So as far as the cab goes, I really had everything I needed.
2. Availability of repro artwork. Arcadeshop carries all the Centipede repro artwork you need for the cab, minus the marquee. I won an original Centipede marquee on eBay for $9, so I was all set.
3. Having a dedicated Centipede cab is just plain cool.

Regarding the board, a friend gave me a Centipede board because it didn't work. There was a blown cap on the board, some contacts on the edge connector were burnt right off, and there was a big gouge across the back of the board that broke a number of traces. I repaired the traces and then fixed the burnt GND contact on the edge connector by soldering on some 10ga wire to the board trace and tinned the end of the wire. Then I used a dremel to grind the wire into shape so it would fit into the edge connector.

I plugged it in and it came up with just garbage on the screen. I figured that meant I a bad 2101 ram or two, so I started poking around with a logic probe. As I suspected, I discovered 3 bad rams, but I didn't know if that was the extent of the board trouble. Seeing as the GND had been burnt off the board, I wouldn't have been surprised if there were multiple fried components. So, I figured I would send it to an expert to go through the board. I sent the board to Mike Haaland (mikesarcade.com) and asked him to repair it for me. Guess what, he replaced 3 bad 2101's, and that was all that was wrong with the board! Should have just gone with my gut on that one....
But you are correct, it is just like having a brand new cabinet now. In fact, all that minty new artwork even makes it smell brand new...