Unless someone has had personal experience with a Hantek product, I'm reluctant to consider them. I bought one of their USB scopes years ago and it was absolutely useless (trigger was worthless and software was insanely buggy). I tried several brands of USB scope at that time and the Owon USB scopes were the only ones that were low cost and still performed well. I understand Picoscope is also quite good. Anyway, I relegated Hantek to the "toy" rather than "tool" category at that time. Has it changed?
I've also seen the Jun(c)tek products and was amused by the name (and glad to see they've changed the labels on some of their products being marketed to the English speaking world). Unfortunately, the JDS2800 and JDS2900 are not really the products I'm looking for because they're not stackable.
I'm looking for something flat on top and bottom (like the VDS scopes:
http://www.owontech.com/digital-oscilloscopes/virtual-oscilloscopes/vds-series-virtual-pc-usb-oscilloscope.html) that I can have unobtrusively on my desk as part of a small stack of unobtrusive test equipment. For buttons and knobs, I already have bench-top generators including a couple of 2.5GHz RF SigGens and a Siglent SDG2042X (hacked to 120MHz).
I've been surprised at how often I use the VDS scope even though I have several vastly better bench scopes. Because it sits unobtrusively on my desk (under my phone!) and is always there when I need to make a quick measurement, the VDS is probably my most used scope. The PC interface is also great for grabbing images for documentation and showing remote colleagues an active trace over Skype/Zoom/whatever. Sure, I can hook up a bench scope and do that too, but that takes time...