I love the YouTube videos demonstrating all of the different voicing possibilities of a Custom 24-08, but I haven't been able to find any in my neck of the woods. Can anyone who owns a 24-08 tell me how useful they find it over a 24?
The regular Custom 24 offers 5 different combinations but you can't use the Humbuckers individually as 'split' coils. The Custom 24-08 has the ability to split each humbucker individually. You get a 3 way switch so you get 8 different possible combinations - BH, BS, NH, NS, BH & NH, BS & NH, BH & NS, BS & NS (where B=Bridge, N=Neck, H=Humbucker, S=Split).
How useful you find that will depend on you and what you want. You can effectively run the guitar as a Bridge Humbucker and Neck Split for example and just use the 3 way to switch between them. You could run it as two split humbuckers if you want too. With the Standard, you are a bit more limited in that you can only use it as a humbucker guitar and although positions 2 and 4 do offer a split humbucker in one or both, they are also combining both - more variation on the middle position rather than offering a single split humbucker on its own tone.
the 24-08 does offer a few more options (BS, NS, BS & NH effectively) but its really dependent on whether you want or need these options. Personally, I would go for the 24-08 if I had the money and didn't already have a Custom 24. Whether I would use the extra 3 options or not wouldn't factor in to my decision - its better to have and not need than need and not have - its also cheaper than having to buy another guitar if I found I needed those options later.
I have the same options essentially with my 594 as that offers push/pull pot splitting so I have the 8 options a Custom 24-08 offers - different guitar and PU's of course but I still have the option. I find I use it like a traditional Les Paul with just the humbuckers and the 3 way - rarely (if ever) ising the option to split. I still appreciate the option though should I ever need it.