Yeah, I actually have a Magneton powered to L34 with Thunder Shock/Zap Cannon (wish I had kept a Discharge one from back in the day but I'm happy with this one). It's pretty hard to gauge individual performance in Lugia raids but Magneton can usually get off 2 Zap Cannons if you dodge one of the charge moves. Its HP is really terrible even at high levels so I wouldn't recommend powering it up unless you really like Magneton/have a lot of spare resources.
It does evolve into Magnezone in Gen IV so it's definitely not the worst Poke to pour dust into.