First impressions - the Jupiter-8 sounds *great*, an subjectively feels much more alive than the Arturia plugin.
The Juno-106 sounds good, only had a brief time spent flicking through some presets, but in general it's not as nice a sounding synth as the JP8, for me at least. How accurate these are I don't know. With the chorus modes switched in, the noise is faithfully generated, which may be accurate, but was a little disconcerting...
The System-8 is a weird one, kinda like the System-1 before it - sometimes it sounds a bit cheap and plasticy, and then you come across some patches than sound great. The Sys-8 does have some lovely smooth powerful stuff in there though, so will probably reward some deep diving.
As the other plugins, the interfaces are small, and though they can be resized larger, then look blurry as it only uses the one set of graphics at the smaller size. (Note to the Roland - if you only want to include one set of graphics, render them for the *large* size, and then resize downwards...). And the controls are small, steppy and fiddly as before, and I think only respond in that crappy circular fashion.
Did I say the JP8 sounds great?
