In all honesty I think GW in general is just hard to beat regardless, but for dealing with mom grim lavamancer can usually eat her with ease. Unless they have 2 out, you can grim her eot, they save her, then you kill her on your turn. It's not a great solution but it does work. Dealing with both mom and punishing fires together is a bitch though. I'm not really sure any tempo deck in the format is able to deal with maverick that has both mom and punishing fires available.