v4.0 [Dec 17, 2014] May include unspecified updates, enhancements, or bug fixes.
v3.3 [May 2, 2014] SuperSpice is now available as a 64 Bit compiled version.
LTspice IV - a high performance simulator, schematic capture and waveform viewer
Design electrical circuits for complex installations.
Use analog circuit simulation for the professional circuit designer.
Most commonly used analog circuit simulator today
It is the most complete and high performance solution for electronic design.