I don't think there is that much of a difference whether the loaf pans are glass or enameled steel (or even aluminum)--my grandmother made successful loaves in both, though she preferred glass (pyrex), perhaps for ease of cleaning??

It is harder to find rapid rise, dough-conditioned yeast in packets, but other than that, I don't think there is any difference. I have a prejudice for the stuff in the jar, as you can't get all the yeast out of the packets, and I feel, rightly or wrongly, that it keeps better in the refrigerator in a jar--you never can tell if the packet seal has been breached, whereas you CAN tell if the lid is missing.