You want someone who is willing to work and assist you when needed. You should join programs under the same person all the time. This makes for a solid downline. If your sponsor isn't interested in a particular program, contact his sponsor. By doing this, you will strengthen you group.
Many people complain about others stealing their people.
They seem to think that just because they signed someone up once, they should always have them. If someone gives their downline the help and assistance they should, there would be no need for them to worry about someone stealing them away. They should want to continue with you because they know you will help them. Having the right people in your downline is just as important as having the right sponsor. If someone sponsored you into a program and helped you, don't expect them to sign you in another program if you haven't tried to do anything on you own.