I've used both. Right now I'm using a fuse, because, well, I didn't have my breaker around when I ran my power wire. And you can see that in the years since then, it hasn't mattered enough to bother with it.
I liked my breaker (well, sorta, my specific breaker I wasn't too fond of, but there's better designed ones out there), but not enough to care once it's all in. The kill switch is nice, but I can pull my fuse too.
I think if I did everything over again from the start and didn't have a fuse holder already and was just buying bulk wire, I'd probably use a circuit breaker just because.
But the nice thing about Fuses is you can use the same fuse holder for different currents. Say I have a 300A system in it at first, but then I decide I need more room and move down to a 140A system. With a breaker, that means I've either got to go get a new breaker that is rated for a smaller current, or have a WAY too large breaker installed, which is a huge hazard. With a fuse holder, I just need a smaller rated fuse and I'm good to go.
As an aside, the reason I'm not fond of my breaker's design is that it's the normal style with the posts you attach with ring terminals. 4GA or larger ring terminals are big, and that's a lot of exposed conductor using them. If its installed in a perfect spot, that's probably fine. But I'd rather an inline style breaker where the conducting wire is inside of some sort of insulator so it doesn't accidentally short out if something bad happens.