I've used grape, but to be honest, I don't think you can really tell a difference over short periods. I've never tried grape over a long smoke, because I've never had enough trimmings to last that long. About 4 hours was all I tried, and it was mild, but I couldn't tell a difference between grape, apple, or peach. If you have it, I say use it. I wouldn't spend any money for it, and I certainly wouldn't go cutting on the wine vines just for burn wood. Which, BTW, mine are exploding this year. Assuming we don't have another freeze (anything's possible in Missouri) I look to be up to my man business in grapes this year.