Most of my guitars now use 12-hole tie-blocks, rather than the traditional 6-holes.
There are a few advantages – they look neater, the basses are very simple to tie, and they give a more consistent and slightly larger break angle for the strings over the saddle. However, although the basses are very simple to tie, the trebles need a bit more care, and it’s very important to make sure the strings are tied correctly. Poorly tied strings (with either 6-hole or 12-hole tie-blocks) can lead to the end of the string slipping out of the tie-block, whipping round, and hitting the soundboard with some force, causing damage of this type:
To avoid this you need to know how to tie the ends of the strings correctly. I’m hoping to make a video soon, but for now here is a link to a page with detailed instructions including lots of photos: 12-hole tie-block instructions.