This is a bit of a tricky question, as the "best" controller is going to vary from person to person. But if money is no object, the clear winner is the Nacon Revolution Pro. The Revolution Pro has a ton of customization options, including trigger sensitivities, analog stick lengths and programmable controller profiles that can be toggled in real time. Furthermore, the controller's weight can be augmented by adding or removing small weights! These impressive customization options mean that the Revolution Pro can satisfy the needs and preferences of most players.
If you're only requirement is that the controller feature offset analog sticks like the Xbox controller, your best bet is the Nacon Asymmetric. It's a no-frills accessory that doesn't break the bank but does boast the superior Xbox controller layout.