I've been consistently impressed with Tal's products since first trying their free Juno chorus emulation plugin (still the most accurate in my personal opinion). The J-8 is equally exceptional. It can go from ethereal flutes to incredibly thick grinding bass with a few slider tweaks. That is another quality of note - the UI. While still skeuomorphic enough that you won't mistake that you are looking at a Jupiter style synth, but the graphics are clear flat vectors. Their UI's are in my own opinion how all retro synth plugins should look.
But what is most important is the sound and the sound is great. The per-voice modeling helps to create a truly analog and organic feel (something Arturia is only finally starting to do!) You also have the ability to edit those per voice parameters through the 'service control' button (or randomize them) so you can dial in the amount of organic 'character' you want.
I can't say if this is a 1-1 accurate reproduction of a J-8. But I do know that Tal's UNO-LX plugin sounds the closest to my Juno-6 of all the Juno emulations I've tried. And I do know that the J-8 sounds thick and lush. Just go grab the demo and give it a try, you won't be disappointed.