1. Magic: Lots of these in Europe and Central America as well as third world countries. The source and type of the cells being used is unclear. Rather than placing cells in the areas that need treatment, they prefer the more profitable route of injecting them IV. These companies will treat anything from diabetes to spinal cord injury to ALS. This is truly the "wild west" of stem cells.
2. Storage: Lots of these abound. Cord blood, peripheral blood CD34+ cells, other blood based progenitors. While some of these have some science, they all suffer from a lack of the ability to deploy cells to treat disease, so convincing patients to donate cells can be tough. The most successful of these appears to be cord blood storage. The best of these companies are those like Neostem, who have scientific focus and high level medical direction.
3. Big pharma: This is for the most part an off the shelf stem cell solution. The idea is creating the world's next Penicillin. The practical problem is even if this works, it will be many years before the details of treatment protocols are worked out.
4. Stem Cell Application Providers: This would include the Regenexx procedure. It would also include companies like Regenocyte. These groups take more of a scientific approach, use a verifiable cell line, and place the cells at the site in need of repair. They have expereince with actual working treatment protocols for specific diseases.
5. Stem Cells in a Box: These are bedside centrifuge or processing plays. These boxes produce a very dilute stem cell population (like the Harvest system). While they quote big numbers of cells, their literature is grossly misleading. The cell numbers quoted are for CD34+ blood stem cells which aren't usually considered true multi-potent adult stem cells. So while this cell population might help tissue repair in a young person, in a middle aged person and beyond, the stem cell numbers that count are too dilute to matter.