I've no idea how the majority are shaped, but I strongly favour round helipads. The anal compunction of some drivers to align their machines (especially skid equipped) with the edge of a square pad regardless of the wind direction is notable. Back in 1984 I managed to have the pad at Albion Park painted as a circle for this very reason, and I noted last time that I was there it is still a circle!
Dancing around with a 20kt crosswind trying to line up with deck edges is daft, IMO. Or even plonking the skids along the lines of the 'H'
