I'm a 3/10 player but made the 'jump' to 5 strings when I built my first bass and I love them!
I have one 4 sting (which is sadly neglected) and three 5ers which I find more to my preference ... why?
I do not play many really low notes, but the 5ers allows me to stay in one fretting position more then a 4 does, and for those times I need them the low B++ is really useful to me. Bridge spacing is not all that I could wish for, but at the moment I only play a 5.
Sam x