Just curious as to which folks here use.

Tomorrow I get to break in my new Halcyon Infinity 40 BP/W I won at the underwater pumpkin carving two weeks ago. The store manager helped me with most of the adjustments last week, but I had to pull the buckle off so I could put my new knife on the waist belt, plus it needed to be shortened anyway.

I had the 28lb Trianta wing from DRIS with a Hog steel BP and a Hollis Elite 2 harness, which worked well enough, but I could never adjust the shoulder straps. I simply couldn't pull them tight, even after I moved the weight pockets back against the BP and moved the attachment point for the shoulder straps more forward. Someone else always had to do it for me, which I found highly annoying. Felt like a toddler who had to be dressed by mom before going out in the snow. The Halcyon harness has the Cinch option, so adjusting the shoulder straps is just push and pull. I'll switch out my 28 lb wing in place of the 40 lb when I go to Little Cayman next year. Everyone tells me the 40 lb will be too much for tropical diving.

I've been using a jacket style since Scuba Pro first came out with them and see no reason to change.

The BP/W thing is an old system that became popular again; back in the day, we called them BIU- Back Inflation Unit.

I didn't care for'em then and I don't care for the current iteration.

I'm wondering when the horse collar will come back as the latest thing and what it's new name will be...

Neither...sidemount.

One more to add to your list, back inflate bc.

I have all three.  Jacket was used when I had my boat for maintenance....kept me vertical.
Oceanic Excursion II back inflate for singles.  I use AL80's 100;s, and have just picked up a  LP72 steelio.
BP/W for doubles.  I would not choose to use it for singles though, even with a singles wing.  It's sort of regressive in that I would need a weight belt (depends on tank) and crotch strap .  There is no other realistic choice for BM doubles.
Yes, you can add weight pouches, pockets for bu mask, but then that brings it full circle back to the Excursion I have.

@OP; did you try a basic harness with your plate?  As in a one piece strap, non-adjustable.  I do like how easy it is to mount and remove.
I wound up criss crossing the shoulder straps for a better fit.

Keep in mind that all BCDs are not the same. Some inflate at the back and some on the sides.
I started diving back before BCDs were around. We had backplates that just stayed on the tanks. We used a weight belt and had a Mae West style horse collar vest that was only used on the surface. We had no pockets or any place to put them.
When I got back in diving after a too long layoff I had to accumulate the new gear, including a BCD.
I got lucky, and after a lot of reading chose a Zeagle Ranger BCD. Having never used one before it has turned out to be a very good choice for me. After several dives I have become comfortable with having a BCD and really understand why they came into use- they are a big improvement over what we had back in the early '70s.

Many divers prefer a BP/W over a BCD, but keep in mind there are some large differences among the various BCDs out there. It isn't really black and white clear advantage one way or the other.

I made the transition to a BP/W last year and have zero intention of ever putting on a bcd again unless I'm getting paid for it.   I went with one that many bp/w 'purists' don't like.  The Scubapro x-tec form.  It's padded, it has more than 1 piece of webbing, and even *gasp* has more D rings than the approved DIR cult says it should.   I dive it in everything from an underarmor shirt to a 7 mil and I'll dive it with my drysuit when it comes in.  I don't think I'd like webbing on a thin underarmor shirt, or no shirt. I like the padding, and don't much care what anyone has to say about it. If I was always diving dry or in a cold water wetsuit, a plain plate and webbing would be fine. But I dive in 88-90 degree water too.

It doesn't roll me forward any more than a jacket style ever did, contrary to what a bunch of people that have never worn one told me it would.

same here