I hear a lot of "it isn't worth wasting your mega slot on". I think as the metagame settles down, people will realize that you can make a good team without a mega fairly easily. Once that happens Manectric will see a lot more use ironically. You don't need to force a mega onto every team, and last gen there were many teams that used Jolteon and Thundurus-T. If the team that you've built has a mega on it, use one of those two. If it doesn't use MM. It'll be fine and get decent usage.
And seriously I saw some people saying that losing immunity to electric attacks is bad....it gets Intimidate for it....one of the better abilities by far.
And seriously I saw some people saying that losing immunity to electric attacks is bad....it gets Intimidate for it....one of the better abilities by far.