Maybe I’m a printer snob, but I bought an I3 mk3 kit at the beginning of the covid shutdown. Never had a problem assembling it or getting it to work. I’ve used it a lot since then. Only recently have I had to make a repair. I’ve gone through several print surfaces and never even changed the nozzle (I should have, it got encapsulated in plastic and caused me to have to replace the hot end)
I have a friend who I finally persuaded to step into the water. He bought an Ender. It has a slightly bigger bed but only one Z-axis screw. He had a devil of a time getting it to work (and it wasn’t a kit). Said he boxed it up several times to send it back but always changed his mind. He made several enhancements including adding a second Z-axis screw that, unlike the Prusa, is belt coupled to the one z-axis motor. When he finally did get it going he had within a couple of hundred dollars of what the Prusa kit cost.
The mk4 looks to be a quantum step up and as soon as I can get the kit, I will.
It is possible we are using the jargon in a different way. Technically, my printer was called a “kit”, but it required very little actual assembly, just bolting the main structural parts together. I also assembled a large format Creality which was called a “kit” as well, but again just required bolting together the big pieces. When I think of a “kit”, I am thinking of something that requires a little more than just bolting together structural parts.