回复：multiple entry H1B visa

First, if you are not Canadian PR, you will not get a multiple entry visa in most cases.

1). It is easier then F-1, but still some risks.
2). If you r rejected, you will not able to come back to US. Most possible you will be sent to China.
3). Risk for security check is bigger then reject, it takes from 3 weeks to 4 months for such check.