I have no experience with the electronic MH ballasts and am running 'dinosaur' Advance M58 magnetic ballasts to fire my 250watt MH lamps. They work fine and I've resisted the urge and hype to 'upgrade' to electronic. Nothing wrong with magnetic technology. It will use more power than electronic ballasts but I've read that this higher power use also translates to brighter light from your lamps. I came very close to converting a while back, but the more I thought about it, the more convinced I became that there's little reason to change as long as what I have is working.
If a coil or capacitor goes on your magnetic ballast, it's not difficult or overly pricey to replace that component. Try getting parts for an electronic ballast when it packs it in. Not going to happen, the whole thing goes in the trash unless you're willing to send it back for service. One significant advantage of electronic over magnetic is that most newer electronic ballasts can fire almost any bulb, pulse, probe, DE, SE etc. The magnetics need to be matched to specific bulbs. So electronic is great if you're in the habit of constantly changing bulb type.