301s are popular machines due to being aluminum and light weight. Probably the 2nd most popular vintage machine for quilters, the featherweights being first. Bobbin cases are the same for both machines and pricey. I'd jump on it for $50 if the bobbin case is there. The 128s aren't as popular and are worth less but it is still worth the asking price IMO especially if it has it's bent wood case.
Both are good and too bad you can't get both.
Rodney