I think I talked about what I prefered about the Brownbucker above, but if I didn't.....
The '78 is a little thicker and I really like sounds more on the thicker side hence my name "Chubtone". However, what I got with the '78 was more of a dull, inarticulate, softer, mushy sort of tone in comparison to the Arcane. I really liked the '78 over most any other pickups until I tried the Arcane. Then what I felt was lacking in the '78 was all there with the Brownbucker. I think it can be a mistake to just listen for thicker and warmer because that can more easily disappear in a mix.
And I don't feel you can add that articulation to a pickup if it isn't there. I could certainly add more low end or warmth to the Arcane if I wanted to though. Listen where I palm mute while playing on the '78 and it is nearly indecipherable mush and with the Arcane there is this percussive click to the note. I FREAKING LOVE that little click as part of the tone. I find that my favorite players that palm mute a lot tend to have that. And I have tried a Duncan '78 with an Alnico V magnet before and didn't like what that did to the sound. The Arcane with the a5 is perfect to my ears.