Livestrong seems quite reputable to me. They have audited published financial statements posted on the web for anyone to review. They report a low 19% administrative cost.
"We have provided financial resources to more than 550 organizations that conduct cancer survivorship research or offer services to people affected by cancer, and 81 cents
of every dollar raised has gone directly to support our programs and services for survivors."
BTW, I'm a big supporter of the American Cancer Scoiety and also the NCI and have worked with them but I am not affilated with Livestrong at all.
As as Armstrong is concerned, I am sure he doped but I am also pretty sure that at least half the field in the Tour de France was also doping. With all the sponsorship money, it would be pointless for a top biker to ride that race without doping. Ask Greg Lemond who tried to race dope-free and was overwhelmed by many doped-up riders that he easily outraced in the past.
Whoever the officials eventually declare as the new winners of those past races instead of Armstrong had probably doped too. Its a mess.