I'm finding myself more and more interested in the phone, despite all the commentary about the screen being plastic (Samsung marketing fubar there, if they'd advertised it acknowledging the fact it's a glass substrate with a layer on top, a lot of the current shouting could have been avoided) and such, it still piques my interest in a way few phones have in the last couple of years.
I find myself in the position of being 7 or 8 weeks out from contract term upgrade date, currently running an S9+, with both the S20 variants and the Z Flip slated to be available by that point. So my options are looking like:
S20+/S20 Ultra: Big step up in practically every sense.
Z Flip: Effectively a folding S10 on new software. Much smaller step up in spec, although still better than my S9.
Use case: I mostly use my main camera for shots of opportunity, it never sees much use as a serious camera, really. The one on my S9 is perfectly fine. this, in fact, it pretty much what I have to say about the whole show, the S9+ has functioned admirably in every task I have set it, and I have never really pushed its capabilities to the absolute limit (frankly, if it wasn't for normal deterioration and the problem of lack of software updated at some point sooner than the s20/Z, I could stick with it.) It's things like that that mean I don't see the (clearly better) spec on the s20 in terms of cameras, storage, memory, etc as too much of a plus point over the Z as I'm unlikely to ever need all the extra oomph.
So essentially it comes down to trad, more robust phone with bigger battery but overkill vs folding, fits in pocket better but possibly will have screen life/durability issues. and the cool factor.