Re: I finally tried an RGA121
The X2N needs to be in a bright guitar, like the RGA. It's the hottest passive PU there is so its got tons of power. I thought it sounded wicked in my RGA121 but it was, "meh" in my Les Paul (which is a naturally dark guitar). It's best known for being the exclusive pickup used by metal legend Chuck Shuldiner. The sound is sharp highs but with a lot of chunk - it's perfect for old school metal.
The main problem with it, though, is that since it has such a high output it pulls a hell of a lot on the strings and so you have to set the hight properly so you don't lose sustain. And like I said; in a dark guitar it doesn't sound great. I should mention that with a guitar that screws its pickups right to the body (instead of in a bracket) the body needs to be bored slightly since the X2N is so thick.
Point is when I had the X2N/Breed combo in my RGA121 it was the best sounding thing ever. But a set of Breeds is sweet sauce too!