Ok, having looked up a muffuletta, if wikipedia is accurate, this is what it is:
A traditional-style muffuletta sandwich consists of a muffuletta loaf split horizontally and covered with layers of marinated olive salad, mortadella, salami, mozzarella, ham, and provolone. The sandwich is sometimes heated to soften the provolone.[5] Quarter, half, and full-sized muffulettas are sold.
That actually sounds really damn good, though I've never had olive salad so that could be questionable. I'm not that into olives, but the mixture of it (olives, garlic, sweet peppers, herbs, spices, other various items) sounds like it could be exquisite.
I also looked up the Ribeye Banh Mi, and I know now what it is and have had it. They are ok to me, though they aren't totally my cup of tea. My sister loves them, and it feels like there's a thousand Vietnamese places in Seattle that do them the last time I was there.