Banshee is not great vs poke, it's not bad either though. It shines vs initiation (like those binds people fish all day long, or perhaps wild mumu/malphite ult). Extremely good on kiters to build on. (for example Ashe with that thing will just slow bruiser who will not get his secondary effect from gap closer and walk away, for example Xin Zhao charging it will not get his slow off, and between furor boots, frost arrows and PD/SS there is nothing to keep him in range anymore).
Sunfire is OP as hell, no other item gives so much damage on it's own, but it has some limits.
I don't personally know how good randuins is, because ... well it's a bit weird item at the moment, gives some edge over AD carry, but it's no longer that old item which had killer AS reduction, it's more like just slow/hp/armor item now. But warden's mail, the thing you build it from is extremely good item in lane vs autoattackers. Unlike tabis it also affect on-hit guys like Irelia.
When talking about poke, I think the best item against it is bulwark.