I tend to prefer low- or medium-viscosity versions over gels. Again, it's awful at gap filling, but working on closely mated surfaces means it's great to let the glue get pulled into tiny gaps via capillary action. Low-viscosity is a lot more liable to end up all over your hands or workbench, though.
Oh and the curing can take longer than you'd think, so give it a good several minutes at least before fiddling with it. I've learned this the hard way many times.
One thing CA excels at is mending ceramics. Other than that I mostly put it in the category of "quick fix" -- really good for temp stuff, but probably not the best option for anything meant to be genuinely durable.
@Felthry sugru is a silicone and is generally pretty okay.
@starkatt what is a kneadable epoxy then?