Okay, so I disagree with some things said here.
1) I think "playing the best decks" is a bit too strong. Or can be misunderstood. I think "playing very good, proven decks" is not as catchy, but fits better. You need a general meta knowledge, not a perfect one. The latter helps to win tournaments, but a general feel for good decks should lead you to a good deck, even if it might not be the best for a given tournament.
For example, I'd say for the Worlds meta Temu Whizz and Siphon Whizz were the best Runner decks. But there were also a couple of Runner decks I regard as still good enough to provide a good learning experience: Dumblefork, DLR Maxx, Andysucker, Link Kate, Dyper, maybe also the Geists (Siege Geist/Aggro Geist). I think you should look in that range of best decks, not the absolute top. There is an argument for not playing combo decks for learning the fundamentals of the game, so you might skip those, but you get the idea.
2) Given that definition of "playing the best decks", I really think it is a good advice. When it's about learning the game, you want something reliable, that has working interactions in it. I agree that many good players will recognize those decks and pull off the according counter-play. I don't think that's a bad thing! Learning isn't about winning every game (although winning helps staying motivated, for sure). When you see how good players play around your threats, you learn way more about the deck and the core strategy in it then if you only play against opponents which you catch by surprise.
Creating and playing your own decks is fun. You should absolutely do that at some time. But playing the best decks and seeing what makes them the best decks is such a helpful experience, you should not miss that.
3) I kinda disagree with "just ask, everybody is glad to tell you", because I feel it's not that easy. For example, there is this thread from the same author as this one about "which Corp decks are good and fun at the moment?", and well, it doesn't have much responses. Maybe the question was too specific, maybe Slack would have been a better place, I don't know.
Also, I remember the time just before Worlds when a Stimhack article about Nexus Kate was released. It was a good article about an interesting deck, but a lot of the responses in the forum were like "The most helpful part was the overview over the Corp meta at the end of the article", so obviously a lot of people didn't know.
Asking still is okay, but sometimes you won't get an answer, so that can't be the one and only way to find out.
So how should a new player get that feeling? I think in the end it's "look around you and see", but to be more specific:
- Looking at winning SC lists helps. Not every list there is a match, but lists that occur regularly are probably just good decks. Lists winning big tournaments like Worlds are for sure good decks.
- Follow the streams of some Netrunners. I'm not a fan of playing online, but I like watching people playing in the competitive lobby, just to see what decks are played there.
- Don't forget old archetypes, even if they get out of fashion. They might come back with new cards. This happens a lot, actually.