Been years since I used a Speccy emulator, and I don't even remember what it was called.
For Atari ST Steem is very user friendly.
For the Apple, AppleWin ditto.

Of those three, wouldn't Commodore 64 versions be generally the best? I think at least C=64 could perform smooth parallax scrolling while those two others, and almost all other systems of the time (MSX etc.) struggled with scrolling? And probably C=64 also had the best audio capabilities too?

Not sure if e.g. Amstrad could produce more simultaneous colors on screen or something... In my childhood, I recognized that Amstrad CPC was a thing, but I didn't know anyone who had one, or ever saw it running in any store. Maybe it was more of an UK thing. I knew someone who had Spectrum, and several had Commodore 64s.

Amstrad was very popular in France and a couple of other European countries. Spectrum was of course the big one in the UK.
The Amstrad was a very capable machine but unfortunately a lot of its games were rushed ports of the Spectrum version and wound up being inferior.
People often assume that C64 had the best version of games but often the Speccy was superior. It all boils down to the individual programmers and the type of game as each computer had its strengths and weaknesses.

And then sometimes the NES/FAMICOM comes along and throws a wrench into things by being an entirely different game. Like so.

Yes, I always assumed the same as it was always pushed that c64 was better. Never really played much on one so can’t give a comparison. Spectrum would be my preferred, but ok to keep all.

Anyone on the GBA vs DS? Not overly interested in the touch screen part.

I've found that games do tend to feel better on their "home" systems. Games made primarily on the Spectrum don't feel quite right to me when ported to the C64. I played the C64 a lot as a kid but revisiting it and comparing it to other systems, I've found it to be distractingly slow and choppy in the gameplay in many cases. It has a wonderful sound chip, of course. The Spectrum in comparison gets mocked for its limited graphics but the trade off is that its best games play really fast and smoothly.

Revisiting the Atari 800 has been a bit of a revelation to me because so many of its games just feel so good to play and are very accessible while still looking quite nice and sounding pretty good even if not nearly as good as the C64. Of all the 8-bit generation of PCs, I think it might be my overall favorite.

I've gotten more into exploring the Apple II. It definitely had its limitations but once you get used to its quirks, the games do have an odd sort of appeal. The Apple II version of Windwalker has some really cool music in the intro compared to the DOS version.

I am less familiar with NES versions of games (besides playing Super Mario Bros and Final Fantasy games on it), but yeah, I've seen that odd trend that NES versions of various games are something completely different. I recall e.g. Gauntlet being that way, not quite much as Bionic Commando though it seems.

In a way it is refreshing I guess (not just having yet another slightly different version of some popular game), but then it feels odd that the game is not trying to be a close replica of the original (e.g. the arcade coin-op version), which is what at least I usually wanted as a kid, as close (or sometimes even superior) version of the arcade game.

Mmm, might have to look at the Atari 800 at some point. Never had an Atari, so no exeprience with them. They always seem to be overshadowed by the Amiga systems. Apple I am afraid never interested me, and doesn’t to this day, even though I have an iPhone and iPad.

Was just looking at the net at these and it led me to search for bbc micro, now there is something I haven’t seen for quite some time. Remember connecting circuit boards to one of the ports and creating a traffic light system in code with one back in school. Happy days. Nimbus networks with granny’s garden.

I have a recollection that Atari homecomputers (not the VCS video gaming console) and Apple II were more of an American thing, and less used and available in Europe.

As a kid, I recall once seeing some Atari computer (someone was playing Pac Man on it), and at school we had some old Apple II computers in the computer lab, which I used (and played e.g. Ultima 2 and 3 on them). Other than that, I didn't know anyone who would have Apple or Atari computers, but my big brother, who had been an exchange student in US, told that especially Apple II computers were very commonplace there.

Another such thing is TRS-80. I recall seeing some pictures of its games and felt wow I want to have that! But I think it was mainly in US, never saw it here.

I even recall trying some Australian home computer here in a store, I think it was called MicroBee or somesuch.

I mean at the end of the day, you have to consider the longevity of console games vs their price, after all what was the C64 version but a few markka; such that even a child could easily purchase in a shop, whereas a NES game (if even existent in your region) would cost an actual salary.

If I'm not mistaken, the European equivalent of the TRS-80 was the Dragon 32/64. They're apparently close enough in design that software made for one can work on the other.

Not heard of either of those unfortunately.