Since MSX was a standard licensed platform, the machine's internal hardware (CPU, VDP, Sound, RAM) were the same because they needed to all run the same software. This is aside from any expansions or peripherals the manufacturer may have chosen to bundle in the box. In general, such add-ons can usually be added via external cartridge anyway. The other thing would be retrofitting any video mods such as S-Video or component out. As with most 80s machines, that's mostly handled by modern kits you buy online, so you'll just want to check that your chosen machine is compatible with any add-on kit you want to hack into it.

Otherwise the key difference is down to which external form factor, design, colors and keyboard ergonomics you prefer. As for x68k, that's not an all-in-one so it doesn't fit my collecting profile. So, I know little about it (though I'd certainly love to have one anyway). It's a pity I was selective in my profile because I acquired my collection in the late 90s when most of these machines were free or near-free. :-) As it is, I managed to get clean, complete, working examples of every Commodore, Atari, Sinclair, Amstrad, Dragon, Thompson, Radio Shack, etc that were all-in-one - as well as most of the MSX machines and many clones and one-offs. Well over a hundred unique models and I never paid more than $20 + shipping for any of them. In fact, I haven't acquired any retro computers in the last 20 years since my collection was already complete by then. :-)

Almost the same story. I mostly stashed away computers I had like comodores, amigas, spectrums etc or exchanged with fellows in same hobby. I also had luck that I worked with SGI machines, even though I love my amigas (3d work at the time). My primary interest are consoles, of which I managed to get a full set of few (snes, n64) in time. I think "I'm done" though, except these two. Maybe Sam Coupe as the ultimate in Spectrum story, don't know. When you say every Commodore.. surely not the 65 too?

The Sam Coupe is cool. IIRC, I have two, one of which is some kind of special red one they sold. I'd have to go dig it out to know for sure but I do remember being fond of the Sam Coupe's funky looks (especially since I never used, or even saw one, back when they were on the market). I have all the Spectrums and, yes, a C65 (I was deep in the Amiga space and still stay in touch with some of the OG devs, so my Amigas are now signed on the bottom :-)). No Apple 1 but it wasn't sold in a case anyway. But I do have all the Apple 2 and 3 flavors.

Of course I never imagined these machines would actually become valuable collector items someday. They were just worthless trash that I was 'weird' for wanting to keep. According to my daughter, who looked up selling prices of some of the machines, the value of the collection is easily in the hundreds of thousands of dollars. Oddly, this news didn't make me happy. Instead, it feels weird and somehow makes what started as a quirky nerd hobby a lot less fun. Now people act like I'm some kind of savvy investor who was secretly acquiring under-priced assets ahead of "the market". I liked it better when this was all junk no one wanted, and I was just eccentric for loving the stuff.