Chris from Classic Gaming Quarterly just posted a review of Retro-Bit’s Big 6 Genesis controller. He compared it to both 3 and 6 button original controllers and demo’d it with three classic games. Overall, he seemed to like it, but noted that sometimes the d-pad would register an “up” press with minimal pressure compared to the originals (demo’d in the video). Beast also received his and seemed to like it, so these seem like a safe buy. Sadly, the USB version doesn’t seem to be in stock anywhere, but CastleMania Games has them for pre-order and they should ship when they arrive. Also, as usual, no lag test numbers have been posted ;/
As a note, one of my original concerns was the placement of the Start button, but both noted that wasn’t an issue at all. I didn’t expect it to, but it was something to look out for!
For me personally, the original, 3-button Genesis controller is second only to the SNES controller. I use it every chance I get, unless the game would truly suffer without it (SF, MK, etc). I’m really looking forward to trying the USB version on the MiSTer and if I have time, I’ll lag test it. And I’m also looking forward to comparing it to the “original” Big 6: