Normally a Grio Chronicle for mtb and a selection of Lazer helmets for road, did consider a Giro switchblade but having a removable chinbar that I would never remove seems pointless
When I used to work in a shop (a fair few years ago) I used to find Giros fit fairly in the middle for head shape, Met suiting narrower heads and Bell suiting rounder broader ones.
You also get some different pads with the Proframe to tailor fit.
Normally a Grio Chronicle for mtb and a selection of Lazer helmets for road, did consider a Giro switchblade but having a removable chinbar that I would never remove seems pointless