Sorry, late to the party on this thread. But I was rather shocked about some posts where it seemed the lag is not a big deal. I beg to differ. It's always been my major beef with playing emulators vs real hardware. The timing is off. This is what turns me on to FPGA, as this problem, that emulation can't truly get around(yes I know or retroarch runahead), FPGA solutions can solve this problem. This is a major factor as to why I support MiSTer and its future. A future where the cores could mimic the og hardware, 100%,including input lag.
I'm a former pro fighting game player. Lag means everything. Yes the arguments can be made that if there are 1-2 extra frames of lag. You can eventually get used to it. And sure, you can, but this really only applies to predictable/patterned games with a set path like platformers. You know when the jumps are, where the enemy placement is. Playing RPGs, and other games as well, not too big of a deal. So yes, merely playing with a little lag, you could get used to.
But what about games that are unpredictable, and require very fast decision making? Lag comes into play and greatly affects the game, and the Meta. Let's take Tekken 7. The game requires a ton of knowledge and reactions. A lot of high damaging low attacks in tekken are designed to be just slow enough to react to, if you know what you are looking for and can recognize to. At launch the ps4 version lagged 2 frames behind the original arcade version. Everyone in the tournament scene hated playing ps4. Those 2 added frames, could be just enough to where I can no longer react and block, and punish in time. And now my opponent has access to attacks, that are designed to be reacted to, can no longer be. Now it becomes a guess. That ruins the meta/strategy of the game. Now people can get away with stuff vs an experienced player, in which they shouldn't. Even without the added lag, it's hard to react to because you have another 1000 possible scenarios that can come at you any second, so incredibly fast decision making, based off the constantly changing scenarios, have to be factored in to a humans response time.
The Mike Tyson example holds true too, in much simpler terms.
Going back to the "just getting used to it" mentality. While I said yeah, you can get used to it, on specific genres, and predictable/patterned games. But what if I play on Mister, get used to it, then go back to OG hardware, now I'm thrown off, then I go to emulator, thrown off again. That is frustrating
I think the whole "get used to it" mentality is a real bummer to hear, especially from bigger people involved in the project. Isn't the point to shoot for accuracy? If so, input lag goes with that accuracy. It should be one area that makes fpga superior to emulation. I'm not shitting on anyone's work or the project, as I think everyone is doing an incredible job, and am super appreciative of this whole project.
I just feel it's rather crazy to brush off 1-2 frame as negligable. Maybe to some people it is. But there are many people that are very hardcore and those frames matter A LOT. Just because it feels good to you, doesnt it mean it feels good to everyone else. Another person may be playing more complex, timing intensive games, or just playing the games at a much high skill level that requires more from a player.
This is why I bought things like a super NT. Accuracy, especially with input lag, while also giving me options like an emulator, and playing on a modern display. That's really where my hopes lie for MiSTer, in the future.
Sorry long post
Tl;dr. Input lag is a big deal. Let's not try to pretend it isn't.