Old virtual analogs like the AN1X, Nord Lead, MS2000 etc are interesting because they had very little computing power and had to rely on a lot of interesting proprietary code, hacks and workarounds to be efficient while still attempting to replicate analog. They didn't sound analog but all the little algorithmic tricks made them sound unique.

Now most of the virtual analog synth plugins you own sound pretty similar. They sound closer to real analog but are using a lot of the same stock algorithms.