The green card lasts forever, and permits one to work, invest, study or do none of the above with complete freedom. Green card holders are subject to US world wide taxation and must make the US their permanent residence. Green card holder dependents also receive green cards valid for the rest of their lives.
E visa holders may only work for themselves or the E visa enterprise. E visas may be extended as long as the E visa enterprise is operating. E visas are generally issued in five year increments. E visa dependent children loose their E visa status when they turn 21 years of age. At that time they need to find another status. E visa holders and dependents may study in the US. E visa holders do not have to live in the US any particular amount of time and may arrange their affairs so they are not subject to world wide taxation.
Those wishing to retire in America, live in America say six months a year and have no kids under 21 years of age, should consider an E visa investment. In this case the E visa is more flexible both for tax purposes and there’s no requirement to come to the US for at least one time every six months. The US does not have a retirement visa category. The E visa is as close as it gets.
Families with young children need to consider the fate of their children once they turn 21. In this case green cards are the better alternative. If a green card is not possible, then consider that children can go to university on F1 visas, upon graduation qualify for H1B visas and at some point they will get married, more than likely to a US citizen. If you don’t qualify for a green card and don’t want to expose your children to the added immigration pressure of having “ify” status then stay home or invest under Eb5 below.