Che was tracked down by U.S. backed Bolivian troops, captured and murdered at the behest of the CIA. Che was a real revolutionary who practiced what he preached and genuinely cared about the down trodded masses; Castro just wanted power.
The only reason for the embargo has been the political influence of the exiled elite Cuban community in Miami. They're pissed because Bacardi had to move to Puerto Rico!
Perhaps if Che's dream of one united Latin America from Mexico to Patagonia would have been realized( which was also the dream of the Liberator Simon Bolivar), you wouldn't have the large influx of immigrants from Latin America (legal or otherwise) that you do today.