Play it turn 1, it's a 1/3 mech that'll only grow healthier... With magnetic this could become an issue if not dealt with. Or you could be playing this as a 1/2 late game and it does basically nothing.
It's a 1/2 until the turn after you played it, which dies to a lot of things. Then it's vanilla stats, and then, on the second turn after you play it, it starts to get good. I think it's pretty mediocre.