It depends, but here's my opinion on those shows
Decade- Not a good show, characters aren't likeable, story's forgettable and gets all the Riders wrong
Black-I haven't seen it because whenever Black uses a finishing move, the screen flickers a lot which really hurts my eyes
Kabuto-Good characters and visually one of the best, though the story's kind of ass and the main character can be somewhat unlikeable
W- Perfect show. Great characters and a perfect mix between action, comedy, story and character development

Kabuto is a fun show with a lot less cgi than the neo-Heisei era that started with W. It depends if you want to watch something newer and closer in tone to the rider series of the recent years. Black is an amazing classic and it's a lot easier to get in to than the original 1970s series. The actor even came back twice to reprise his iconic role in Decade and Drive.

If you want to get into Rider there's only one right thing to do: Start wherever you want. It absolutely doesn't matter where you begin, unless it is a straight-up sequel show like Black RX, in that case, you do better watch Black first.

Other than that? Watch what you want. Some people might say don't watch Decade first because it features all the other Heisei-era Riders (but it doesn't matter, they're different from their original selfs anyways) or that you should start with the first show, Kuuga or W to get an idea what Rider is about but I say: Screw that.

Look at the suits and gimmicks, read a short summary of what the show you're interested in is roughly about, decide on what you think will entertain you the most and watch it. After that, you have a much better idea of what you can watch next because then we can tell you which shows are similar or what you might like based on what you enjoyed about your first show.

And after that, you have a good idea about what you like about Rider and can pick anything else yourself.

There is no perfect show to start, you could hate shows most of the fandom like and the other way around, thus it is pointless to tell you what you should start with.

I started with a show which was very different from the norm and immediatley watched what consider most to be one of the worst Rider-series in existence, yet I still watched a lot more and love it.

While you're not wrong, I do recommend on asking for recommendations and the reasons behind them so that you know why those particular seasons are so beloved

Yeah, I don't think it is bad to get some recommendations first to at least steer you away from some of the more controversial seasons to start. I nearly watched Hibiki first, which frankly would have been a disaster!

It doesn't hurt to ask what we think about a certain show when you want to watch it, but I so tired of people going around like "Watch this first, you have to in order to get what Rider is about" when someone wants to get into Kamen Rider. That's just so stupid.

So I'd say make a list of stuff that could interest you the most and then ask what people think about it. But even then you're asking strangers and you have no idea how well their preferences line up with yours, it's not like we're critics with a track record or anything.

That's why I say try it yourself first. If that really stinks you can still ask if you got a lemon or if you just don't like what Rider does in general.

Oh yeah that. Fuck that

Thanks you guys. I'll begin with W then.

I'm a Drive fanboy so I will always suggest watching Kamen Rider Drive as a go to. It slightly differs due to Drive not having your usual bike and instead uses a car, which in itself is pretty badass. It starts off pretty high for the first like 5 episodes, but slows down until it hits the 15-20, and picks itself back up going forward with a nice constant pace.

I'm always happy to steer people towards Fourze.

It's a goofy, fun show with a loveable cast with no real high stakes until the very end, and even then it ends on an unambiguously positive note, unlike most others. Yeah, it's different from everything else, but that's not necessarily a bad thing.

Plus it gave us Space Bruce Lee and the funkiest belt yet.