Last year I have done several tests.
I compared several anlog chorus units, old and new as well as digital units. My aim was for a warm subtle solution.
More intense thick chorus sounds would have been a different topic.
The winners were the old blue CE-2 and the classic CE-1. Also the Chorus build into the Ibanez UE-400/405 was top notch.
The Boss CE-2B was not as good. All newer pedals (such as MXR M134), analog or digital were not on the same level, including large Strymon, Boss 500, H9 units and some rack gear. Also CE-1W is not the same as the CE-1.
If you want that subtle chorus sound, it seems the older BBDs simply sound better.
Obviously, I didn't have every product in the world.
My aim was to create such sound in full stereo format which obviously a Strymon Mobius, Eventide H9 oder Boss MD500 would do really easy. However, the old versions were simply superior to my ear, so I went for two CE-1 silver screw units. I single CE-1 would be fine if you run a mono in stereo setup. I run dry/wet/wet however ...