The Giros are pretty nice, great FOV, I like the looks better than the I/O as they are lower profile. They are too tall for me to wear the helmet low, sadly.
If you are S/M I think the Marshalls are the winner for sure, especially as the price is more reasonable. The Giros would be huge on you. If you go with the Marshalls, make sure you pull the ends of the strap and remove the black plastic clips inside the goggle frames. They appear to be unnecessary and force the folded strap ends into your peripheral vision.
Thanks for the suggestion, no one locally deals Anon, and I am sick of ordering things to return. I'm picking up I/O from my local shop today.
Hopefully in the next couple of years companies will put out some goggles that are extra wide, Providing good peripheral, without being so tall that they interfere with helmet fit.