Infernape is one of those Pokemon that CAN run many sets, as it has an awesome movepool, but imho only mixed and choice are really viable. it's too frail for setup, has few notable resistances, and if really hurt by rain. furthermore, it has numerous counters, all of them common, such as dragonite, lati@s, tentacruel, jellicent, starmie, and probably other that i've missed, so pulling off a successful sweep is unlikely. it's also pretty easy to revenge kill with any half decent choice scarf user. breloom's mach punh and stuff like aqua jet also take their toll. it's no wonder infernape isn't the top threat it used to be.
i'm going to be testing a set with toxic.. although i dont know if i'm gonna go mixed or physical. physical would probably be better as i can run flare blitz/cc/thunderpunch/toxic, as toxic is ineffective against tentacruel and starmie, while thunderpunch can mess them up on the switchin. all the other pokemon mentioned are pretty much crippled by a toxic. but yeah obviously his set relies really heavily on prediction, so it might also be feasible to run substitute over thunderpunch, in a similar way to subtoxic heatran. i'll post on my experiences once i've tested it.