Ive never worn a Giro Shiv but i love my Poc Receptor Bug. It isnt crazy light but by no means is it heavy. For a beanie underneath you can really customize it to your liking between taking out the ear pads and parts of the liner. I dont wear a beanie underneath but have heard good things about it. Pricewise the Giro Shiv is about $80.00 and the Poc is $120.00. Yeah the poc is a good bit more but i believe with a helmet you should spend a little more, and you get alot of extras with the poc. I got a complete set of extra pads, a bankers brim, a goggle holder, and a nice helmet ban. I vote for the Poc.