I've been writing physical simulators since 19751. Speaking from benefit of the perspective of having written physical simulators for some decades, I see the best simulators developed by the concerns that actually need them and not software companies. I wrote LTspice explicitly to outperform analogous tools for sale from software companies in the interest of having the highest performance SPICE program available from anyone at any price. LTspice is used in-house for IC design and has become part of Linear Technology Corporation's strategy for developing high performance analog products.
What is unusual about LTspice is that is it also freely distributed. Linear Technology Corporation does not freely distribute LTspice out of a charitable interest in the wellbeing of mankind. We are a for-profit organization freely distributing LTspice in the interest of helping customers simulate LTC products with a better simulator than is otherwise available. Further, the freely distributed version of LTspice is exactly the same as us used in-house for IC design. No version of LTspice is crippled in anyway to artificially limit its capability.
This is a unique situation for a SPICE simulator and has made LTspice's popularity no less than fantastic. LTspice is overwhelmingly the most widely distributed and used SPICE program in the industry to date. It has become the de facto standard SPICE program.
LTspice XVII is a partial rewrite of LTspice IV with a modern graphics library for native multi-monitor support. XVII also introduces
Version XVII of LTspice comes in LTspice's 17th year of general release. LTspice XVII was released via an international seminar series during 2016. The first public announcement of LTspice XVII was on May 9th, 2016 in Hanoi, Vietnam.
--Mike Engelhardt / 2016
1] For inelastic nuclear relativistic kinematics used at a cyclotron lab when I was teenager.