Personally, I've only ever seen it work well when the transition was a natural one where the buyer was already involved in the business. IE: Long time owner retires and sells to long-time employee.
I know of one franchise sale that worked (old owners were losing money, new owner turned the location around) - but several more that failed.
For the most part, the buyer loses money when purchasing a small business from an unrelated seller. Almost no business truly "runs itself." I would absolutely never recommend to anyone that they buy a small business unless they are planning on being on the ground, on location, actively participating. Good staff is no substitute for personal involvement. Also, it's incredibly difficult for an owner to tell what staff members are really the good ones from afar.