You're argument is based on the fact that the only factor to consider when buying a controller is whether it works out of the box or not.

In large part, yes. I've discovered I enjoy playing games more than I enjoy configuring games.

You also imply that emulating an Xbox controller is in someway too much extra effort, when it's a stock feature in practically every controller software. You may say "you need extra software for your controller to work, therefore it's worse"

Hmm. Well, not exactly. I'd love for my ps3 controller to work flawlessly on all my games. I consider it a better controller. I wouldn't say "worse" (and I don't personally care what you use either way) but the Xbox controller seems to be the only controller that is specifically taken into account, by default, by a lot of games.

but a) for an xbox controller to have the same features as another controller which requires software, it also needs software(eg. XPadder),

In my experience, all the xbox controller needs are the drivers it comes with.

and B) You could use the same argument for other gaming hardware. If I want to use a razer mouse, for example, I need razer synapse. Does that make a razer mouse inferior to any cheap plugnplay mouse? Not at all.

No, but I don't think that's a good example. But let's try this : If Logitech mice had functionality that they performed out of the box, and the Razer synapse required software in order to emulate a Logitech mouse's functionality, and most games natively detected and natively supported Logitech mice in the first place, and if the Razer synapse software required more than a single user interaction (that is to say, installing it in the first place) - if it occasionally required that you had to tweak settings just to the thing to work properly - then I must admit I would wonder why you didn't just buy a Logitech mouse in the first place.

As for your comment about game tutorials...what the fuck are you talking about? What game have you played where that is the case, because I certainly haven't played it.

Let's say you are playing with a ps3 controller. You have it hooked to your PC. Yes, you can get it to control the game. But it's going to say some bullshit like to punch, press button 12. Now, why doesn't it just say to press square? Because, while you can control the game with your controller, your controller is not supported. If you have not run into anything like this, I am sincerely happy for you.

Another benefit to using a controller that is officially supported by the game is that the control scheme is already setup for you. If you are using some kind of third party controller like the ps3 with its drivers, the game is not aware of which button is actually on what position on the controller itself. It cannot direct you too, for example, press the left trigger, when it doesn't know if input 14 or input 15 is the left trigger. But what about the controller scheme in general? Since the game has no idea which buttons are where on your unsupported controller, it is up to you to go on the internet and look up the control scheme for the game you want to play. You'll have to find a picture of a ps3 controller or an Xbox controller that details which buttons are kik and which buttons are punch, and then you'll have to match the correct input with the correct positioning of the buttons. Again, if you have never had to do this, I am happy for you. I found this to be the case in my experience far too often.

Your point about support vs. working is only effective if the difference in end result was significantly different, when it isn't.

No, I believe the point to be effective if the difference in the process to get to said result is massively different, in this case, 1 is easy as pie and very convenient, and one is much less so.