Those grinders are all basicly the same made in china with dfferent names on them. I bought one from Harbor freight when they were just mail orders back in the 70s and I use it once in a while . When you get one be sure you get a stone to clean up the wheel . Check out Harbor freight , I don't know what you are going to use one for so if it's not an every day thing I would go for cheep Harbor Freight. as for the drum sanders I have been doing this for 40-50 years and I prefler the sanding mop.
IKE