I'm not familiar with the Marmot Helium, but I once had a Marmot Hydrogen. It was a lovely bag! The only thing wrong with it was that it wasn't warm enough for me. It was true to its current EN13537 rating of comfort rating (cold sleepers, alias women) of 39*F. Of course Marmot didn't use the EN ratings back then.

The main difference is that both FF and WM bags are made in the USA, if that concerns you.

"Eenie Meenie" can be rigged, especially for two items, if you start with the item you don't want. (With three items, start with the one you do want.) Flipping a coin won't work now that 3 bags are up for consideration. That leaves rolling the dice! Good luck!