Honestly, you can play whatever. It's more important to learn fundamentals of neutral game (spacing, when to block, when to go in) than it is to have a proper control scheme. Do what makes you feel most comfortable.
Street Fighter
Community dedicated to Street Fighter
This is the best opinion, and somehow you never hear it.
SF6 is my first fighting game ever, and I have complex feelings on this topic.
When I started I intended to use modern controls as an easier way to get into the game. But after an hour or so of playing, I wasn't having fun. Mainly because of auto combo. I got too much for free and didn't feel like I was earning my wins. If it wasn't for auto combo I probably would have stuck with it.
So I switched to classic and am grinding my way up the hard way. Currently in Bronze 4 and still lose a lot of matches to execution errors, dropping a super, messing up the one combo I know haha, etc. So I do find it tilting to lose to modern when I know they don't have to go through the same struggles.
I'm sure it's the case that at higher ranks the difference is minimal, but for new players modern is a huge advantage, and IMO way less fun if you're actually trying to improve at the game.
That said, even in bronze I face very few modern players, so it's not a big deal.
Overall I think it's a fantastic addition for people just having fun. I play with my wife and she has much more fun with modern controls than she would with classic.
After many MANY failed motion inputs with Classic on an easy character like Lily, I switched back to learning Kimberly again, but with Modern controls. I practiced her a lot with classic, but her inputs are too intense for me with her combos. My mistakes angered me greatly and I over-focused on them instead of playing the game.
Now with Modern, I can do those inputs a lot easier, but also I make damn sure to avoid Auto-combos. Those are boring and reduce creativity and mixups. They're also a HUGE crutch.
So once I started playing like a classic player but with an easier time with special/super inputs, I really started to just relax and enjoy learning the game and its neutral. Because if I was gonna get continually frustrated by missed inputs, dropped inputs, and whatever problems when it comes to execution in Classic then I definitely would've completely dropped the game by now. But instead it's now been wonderful and addicting!
Although it's very character-dependent on mileage with Modern controls. Kimberly misses her main medium air cross-up kick and needs to use the lighter version. She is also missing her crouch medium punch. But these things are extremely minor with how many other things she can do. I also changed her grab macro to be light and heavy so I can reload bombs easier as well as OD throw them close/far for scare tactics.
I use modern because I play mostly casually. It's not that the command inputs are difficult or anything, but I use a gamepad and it feels really awkward to have to use shoulder buttons for my normals.
I prefer classic because I want access to all 6 buttons. But I don't see the issue if someone wants to play modern.
I use classic because I play on a fight stick and it just makes sense to me. Modern is hard for me to wrap my head around. I'm sure it sounds funny to people who find classic difficult but modern is less intuitive for me.
I enjoy the process of practicing execution and learning new set play and combos. The matches are tense but the training room is zen. Learning a combo or setup feels much like learning a new song on guitar, and when you finally get it, it feels great!
I also play Kimberly and personally I worry that modern is a large handicap for her. I use the buttons she is missing on modern very frequently. Without her install, she already has low damage and it hurts to have much of that cut by an additional 20%.
Even though I don't use it, I'm glad so many people like Modern. It's awesome that the genre has more players now. I think those that get upset about getting beaten by modern are forgetting that the other player is beating them in neutral and on timings as well. They aren't being carried by the controls like some would like to believe.
I use Modern.
I haven't played a street fighter game since 3 alpha, and have spent more time playing smash bros than anything else, making Classic a difficult change. I very much enjoy the neutral game more than memorizing combos, so the auto-combos are nice too.
I really wish I could choose the layout of the abilities, though. Some use the same button but with a different delay or hold, and I wish I could just do both.
I prefer classic since I grew up with it, but modern controls are completely valid and it's a shame to see the way so many people treat Modern players. I don't think it reflects well on the community to push away new players when most people will never be at a level where modern vs classic is the deciding factor in a match. Getting salty when losing to modern players or using it as an excuse just encourages toxicity towards beginners and those dipping their toes into the genre.
@alejandro
Classic when playing against others. Modern for World Tour and trying out a character in Arcade mode. Starting out, it's fun to see an auto-combo and then bring it over to classic.
Don't really mind going up against any control type/character. What controller, execution, and reaction times already varies across all players. I'm having more fun when people are making decisions and executing what they want to.
Classic.
Modern could be interesting, but I can't be bothered to deal with learning it just yet. I started learning Chun Li. I can't imagine how her stances would fit into combos on a modern control scheme. EG - it just isn't possible / goes away? Ew.
Modern so far, but I will likely change back to Classic at some point. I find it has been fun playing around with Modern, especially in World Tour.