The general strike was, according to reports I received from Venezuela, much less successful than the one called in December. It is important to remember that workers had little choice but to cooperate with the "strike" in many cases, as businesses shut down and wouldn't let people work.
Now, the situation with the unions is complicated. Many are controlled by the old pols, but Chavez hasn't shown the ability to attract union members either. In any case, remember that 65 percent of Venezuelan workers don't have jobs -- they either work on their own in the "informal" sector -- e.g., as ambulent workers, or they are unemployed. Even in December, most of the poorest Venezuelans in this informal economy did not strike.
Another point: The media is painting this as Chavez trying to stack the oil company with cronies. It's not about personalities -- it's about whether the government or the company makes policy. For example, the company wants out of OPEC, Chavez wants in.