I bought the Blacktail when I first played it on the GC.
Read an faq sheet about guns and then I realized that the Red 9 is far superior handgun than the Blacktail. That exclusive is killer.
I bought the stock with it. I guess you dont really need it with the Wii version because of the superior controls to aim but I figure its important for the GC version.
I assuming people buy the Blacktail because its the last gun that you can unlock. I guess people think that's its a better weapon than the Red 9 just for that fact.