tax implications of nonresident holding property in series LLC?

[Lance Luvaul]

"With regards to Nonresidents of the United States, it is not wise to believe the LLC is generally the best solution for your business needs, as there may be self employment taxes and estate taxes involved that could be far higher than any corporate income tax you can imagine."

The above comes from the website of a lawyer I intend to use to help setup my series LLC. But before I do, I just wanted to get peoples' opinions on what taxation dangers to watch out for (I am a US citizen but no longer live or work in the US). Can anyone elaborate on the 'self employment taxes' and 'estate taxes' the warning mentions? How do I tell if they apply to me?