Technology evolves and changes in time. Older units had a very colored sound, while newer ones are more linear in their character. It's a matter of taste. I prefer newer sounding devices because better filters and reverbs are possible and color can be added (Vsig) if you know what you are doing.
Also, the platform openess is something that has immense value. I just can't think of using anything else where I'm not allowed to change the fx structure.
The 4000 sounds more similar to the 8000 than the 3000.
I think every Eventide is special, anyway.
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