Employment by US company: Did that for five years working remotely from Germany for a US Incorporated. I'm German, had a German contract with all the standard provisions for Germany (mandatory vacation, termination protections etc, employer contributions to health-care etc). Worked without a hitch, like being employed by a DE entity. The only gotcha is that my monthly pay would have social contributions and health-care contributions already deducted, but would not have income tax deducted. So you'd have to save up enough money to pay income tax yourself at the end of the year (or quarterly, depending on how competent your local tax office is). After five years the US parent incorporated a German subsidiary, and since then the taxes were obviously deducted as well.

Personal take on tax accountants or anyone in that profession: They're more than useless. As parent poster said, 99% are form fillers, so if you tell them that you're working for a US entity that is not paying income tax on your behalf some of them will flat out say "but that's not even possible" (yes, someone told me that). My tip is just to read up on some topics, band together with co-workers in a similar situation and then just do the taxes yourself using one of the popular services.