It is possible to remove flicker from an NES with the use of processor overclocking, though I don't believe it is terribly easy to do (never really looked into it though). The reason the NES flickers is because it is only capable of displaying so many sprites at once and therefore has to rotate the display of them if too many are on screen, causing flicker.
As for the controllers, I was curious myself about both that Famicom style turbo controller and the "exact" NES replica (I doubt its 100% exact, things like that rarely are). Personally I LOVE the Yobo FC controllers but they only work on a Yobo FC console, not on the Nintendo because the real NES pins are too large, but if you don't mind spending $25 on amazon.com for a Yobo FC you will probably like the Sega Genesis feeling controllers with good response.
good NES controllers
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