Slowking is really, really good right now - it makes an excellent check to Rain sweepers like Gorebyss and can switch into most Espeon quite easily. Choiced Fire-types can't touch it, and it can freely switch in on them - without Life Orb, Scarf Magmortar is 50-50 to 2HKO max/min/neutral Slowking even if you do switch into T-Bolt. Being able to force out, cripple or kill LO Magmortar is really nice as well, because you can switch in on Fire Blast or Focus Blast, always survive a T-Bolt whatever your spread (I think, haven't run any calcs, but you should always be maxing Slowking's HP anyway) and Thunder Wave Mortar. You can then stall it out with Slack Off and have a decent chance of beating it.