I find all four sentences to be correct and to mean essentially the same thing. My personal favorite is (3), and by far my least favorite is (2).
Generally, I find commas around certain parentheticals less necessary the shorter both the parenthetical and the overall sentence are. Exceptions arise when we have words of dual meaning such as "like" in the position it holds in (2) and (4). If example (2) were presented in a vacuum (as opposed to such a set of examples as this), I could imagine the lack of commas causing some reasonably educated readers to think that "like" is being used to mean "enjoy" or "are fond of" rather than "such as" until they're most of the way through the sentence, at which time they would have to backtrack until they figured out where they lost their thread of thought.