I have both:
One on the bulworks for the furler and two in the back for docking lines. All work but,
The one thing that is very very important! do the very best you can to keep them out from underfoot, as I have said many bad bad words for toe stubbed events when I hit them with my bare toes.
Also remember when healed the lower 4 to 6" of the bull works (pun intended) is a very handy place to put your foot.
The backing under the deck is; as noted; easier to install and do right.
Just my 3cents
Norm