Best: FE10 Ragnell. Respectable usability, great power, 1-2 range. Honorable mention to Thani, which makes its wielder usable and as magic, its armor/cavalry killing power is more useful.
Worst: Durandal. Not only does Eliwood suck at using it, it has terrible usability, and if use it, you hurt your funds ranking. At least you can use Rolf's Bow. It isn't exceptional, but it isn't worse than nothing to use it.
Nominate: Best/Worst RNG