The main difference between Buddhism and Hinduism is the same as the main difference between Christianity and Judaism: whereas Hinduism is a tribal religion, Buddhism is equally accessible to people from any background.
Before Hindu's jump down my throat at the use of the word 'tribal', let me explain what I mean.
A Hindu is defined primarily by their birth, which explains why they're so quick to include Buddha by the way. You're a Brahmin, a Kshatriya or a member of a scheduled caste by your birth. These days there are all kinds of political consequences to this fact.
A Buddhist is anybody who has taken refuge in the Buddha, Dharma and Sangha. That is: you become a Buddhist by choice, comparable to how it works in Christianity and Islam. Like Islam and Christianity, Buddhism is a world religion: it is accessible for everybody and hopes to help every human being (actually every sentient being) towards its version of salvation.
Secondarily a Hindu is defined by what spiritual practices they are involved in: devotion to Krishna, Shiva, Kali etc. The rituals they use to do that have a lot in common with the rituals Buddhists perform for Buddha, but the difference is large:
There is NO claim that Buddha is the primal source of all being. Buddha was a man who attained enlightenment, that's all. Sure, in Mahayana Buddhism 'Buddha Nature' is all pervading, but it's still a long cry from a creator God like Brahman, Shiva or Vishnu.
The reasons for devotion are also different: a Buddhist seeks refuge of the Buddha in hopes of help on their path to their own release from the cycle of rebirth. Hindu's are devoted to their God out of Love and devotion. That doesn't mean that a Buddhist isn't devoted to Buddha, nor that Hindu's can't actively work on attaining Moksha: it's a difference in degree.
For me, as a Western (Tibetan) Buddhist who has looked into Hinduism and Yoga in considerable detail the main issue isn't any of the above difference. I went for Buddhist meditation as opposed to yoga for one reason: ethics and compassion. While in the yoga tradition ethics seem to be an afterthought, in Buddhist practice and thinking about karma it is front line and center. In Mahayana Buddhism the primary motivation on the path is compassion: the wish to save ALL sentient beings from their suffering. I'm sure that sounds like Christianity, but that's another article...
Of course there is one other stickler point: the caste system. There is a reason Ambedkar stimulated whole groups of people to convert to Buddhism: to escape the Caste system. I don't know if it worked, since jati's are a built in aspect of Indian society (as well as of Nepal and Pakistan). Just giving your group a different label doesn't make the system go away. However, the caste system IS supported by Hinduism in a way that it isn't in Buddhism.