Is MacKeeper Malware or Helpful?

MacKeeper presents itself as a helpful program to keep your Mac running as fast as possible. However, once you install it, people have reported slower systems, popup ads and other invasive actions. This sounds like malware, and believe me, it is malware. Yet the confusion comes in because MacKeeper has been reviewed positively on many sites. However, if one looks closely, you can discover that those sites offer paid reviews, and are usually sponsored by MacKeeper. So these reviews are hardly unbiased or objective.

Some of my colleagues' Macbook Pro laptops have been infected with MacKeeper, and they're having a rough time getting rid of it. It's slowing their computers down and causing obnoxious popups.  If anyone has a solution, please post it in the comments below, and I will pass it on to my colleagues. Thanks much!