one of the best VSTIs out there IMHO. its understandable if people got mixed feelings about it though.
it isnt a feature packed monster by any means, just the bread and butter type analog synth. but the point is, it is by far the BEST SOUNDING bread and butter analog synth. i dont know what exactly it is, cause at times it sure isnt perfect, i.e. parameters arent interpolated, envelopes are a bit rough too, but for some reason it simply sounds better than other, similar VSTIs. so its definetly worth the money IMHO, i use it in every song, most of the time one voice for bass and maybe one for some agressive hookline (did i mention the awesome distortion? :-)
plus: best sound. and thats what counts at the end of the day, isnt it :-)
minus: CPU hungry (make sure to mute voices you dont use) the monophonic mode uses highest note priority and not last note priority. thats really totally stupid, cause if you dont edit note lenghts all the time, timing might be off. doh :-)
You won't find it anywhere... given that it was not free. All the copies you will find (except in warez sites but it's not at all my cup of tea) are locked copies used as a limited demo as long as you don' register.
Here is the Wayback Machine copy of the registration page of Mercury-1: