Plus is usually preferable, at least to me. As usual price is hard (and not many of us on the GMB ever want to go there. Motzfedt is very collectible. Still, it depends where you sell it. eBay would probably be the lowest price and you can get some idea of prices there by searching for Motzfeldt in glass, going to advanced search and then checking "completed" to see what they've sold for. I would think that bowls like this would clear a minimum of 70 pounds, and I would expect to pay around 100 pounds to get one of these on eBay. But it's really variable, because some Motzfeldt goes higher and some goes lower, depending on what the individual collectors have and want. Selling through retail is still highly variable, depending on where you're located and what the local antique stores are like.
Sorry to be so vague. Perhaps somebody else is prepared to be more specific.