I do not buy simply because a celeb. endorses. In my area of the country, the big thing on the radio is to have one of the radio announcers plugging a cosmetic studio or various restaurants. The marketing ploy behind this is for the celeb. to talk to you 'just like she/he is your best friend'. There is one radio ad, in particular, that always makes me chuckle. She, supposedly, takes her entire family there frequently (upscale place and she has little kids- under 6 years old). My guess is that they eat there for free!
I do like Marie Osmond- she is of my generation. I think it is nice that she sews. I like Kaye, Nancy, Eleanor, Sue, etc. too. I don't think that I would go out and buy a particular brand machine simply because it is the one that I see a certain celeb using. I would buy the machine that I could afford at my favorite LQS because I trust the people in there.