First post here so I'd like to share my new 2005 Custom 24 20th anniversary PRS which I've had for about a week now. It's an awesome sounding and playing guitar. Incredible playability. I also have a 2011 PRS 513 with a pattern regular neck and it's very similar to the Custom 24's Standard neck. The Custom is a bit beefier feeling though, but it may be placebo from differences between the finishes. My 513 seems to have a smoother finish and the Custom a bit stickier. Either way, both guitars play fantastically and play almost like they were the same guitar.
Sound-wise, the 513 seems more resonant and louder whether or not it's plugged into my amp (I use an Egnater Rebel). The Custom (has HFS and VB pickups) doesn't seem to sound as rich as my 513 but good nonetheless. It's not as bright and strangely, not as warm either. The 513 sounds more acoustic. I tried A/Bing the guitars a couple times and the differences are not that big. In fact, each time I tried to A/B the guitars, I stopped and I rather wanted to just pick one and play. Both guitars are incredibly versatile, but the 513 much more so. The Custom sounds raunchier and never loses that sound. It always seems like it wants to scream which is really fun. However, I'm still a bit new to the rotary system so we'll see what sounds I can get, but I know I haven't been able to get a decent Hendrix "Little Wing" sound out of the Custom like I can with the 513. I'm still very happy with my purchase of the Custom. I wanted something with even more high gain tone than my 513 (which surprisingly is incredibly good at high gain), still very versatile, and plays almost the same. All needs covered.
My 513 is one of the best guitars I've played. I sold my prior Les Paul and Ibanez Prestige after attaining it.