Socially, both tend to be fairly similar

Personal freedom, equality, etc.

From a government perspective, they are both very similar. Both want smaller, less involved government.

The biggest difference seems to stem from their economic view. Right libertarianism would favor more of a laissez faire capitalism, tolerate major corporations etc. Left libertarianism is more of a anti-capitalist/socialist view.

The ultimate failure of both systems is that people must be responsible and morally good (or at least the majority will be). Without restrictions, a right libertarian economy would dominate the left…but would inevitably transform into a plutocracy. Where the wealthy control everything.