On the visa side of things- it can be difficult. While it isn't actually that difficult to sponsor someone for a visa, it does involve more work than hiring a 'normal' employee, and if a company hasn't done it before they may be reluctant to.
My recommendation is to take a job with a larger company to start with. Get the visa that will allow you to be in the US. Network, prove yourself in that environment, then transfer your visa to a smaller startup.
I was under the impression that visas are issued to the company - not to the person - and thus can't be transferred from company to company. Am I mistaken?
On the visa side of things- it can be difficult. While it isn't actually that difficult to sponsor someone for a visa, it does involve more work than hiring a 'normal' employee, and if a company hasn't done it before they may be reluctant to.
My recommendation is to take a job with a larger company to start with. Get the visa that will allow you to be in the US. Network, prove yourself in that environment, then transfer your visa to a smaller startup.