I used to use MSD on my flatwater boat and cooked 3 brains in as many months. I switched to the ATP Total Loss about 3 years ago and am still using the same box. The latest version out is nearly idiot proof as it fits in you stock electrical box using your OEM wiring harness.
I now mainly ski surf and still use the same ATP TL box. The secret IMO is to solder all joints. A pain but thats reliability.
You also get better starting, especially useful if you've had water thro the engine!!, because you get full voltage to the spark at zero revs, not like charging where the revs need to build to give the better spark
The down side is of course the battery, but you should get a weekends worth of skiing, even with the bilge running, providing you have a battery in good condition. Get in the habit of charging every night and carrying a spare.
The plus side is as stated previously, lighter flywheel and adjustable curve of your laptop, far easier to understand than the DIL switches.
There is an added advantage not mentioned. The ATP ignition has 2 different curves which can switched through a bilge pump style switch on you handlebars. This can either allow:
-a low power curve for say riding on the hood and hood tricks on your 8mm stroker which is normally too powerful, or to let a mate learn on,
-a separate low rev limit which is perfect for doing rodeos etc.
-easy set up, which is what I mainly use it for. You can have you main A curve on your normal timing curve, and then dial in a little bit more advance at a certain point on the B curve. You then have a direct comparison, make your wake, hit it on A curve, do it again on B curve and then swap back etc. You can really feel whether the difference is better or worse, without having to got back to the bank and strip the box off etc.
There is another advantage, If you chew bendix as often as me and have them break up, there is nothing to damage in the flywheel cover area.