Well a refresher for people who don't remember the weapons. let me just start off by saying that the Freelancer class can use all of them. Also, the stats are around that area for the base ATK power, I kept finding conflicting information and I wasn't in the mood to dig up my copy of the game to double check.

Here's the rundown:

Assassin's Dagger has 78 ATK, Raises Speed by a point, and has a 25% chance to inflict Instant Death (doesn't work on undead). It can be used by all classes except White Mage and Monk

Apollo's Harp has 42 ATK and ignore Row, does extra damage (like 8x) to undead and demon class monsters. Is actually the best Harp in the game*

Excalibur has 107 Attack power, has the Holy Elemental property so extra damage to undead, and Holy weak enemies. It also raises the Strength stat by 5 points.

Fire Lash has has 79 ATK and 90% accuracy. It increases strength and speed by 2 points and has a 33% chance of casting Firaga while attacking.

Gaia's Bell has 32 ATK, ignores Row, has 99% accuracy, boosts Earth Elemental ATK and has a 25% chance of casting Quake while attacking.

Holy Lance has 107 ATK, Holy Elemental and raises strength by 3 points. Does 2x damage with Jump command like all spears.

Magus Rod has 37 ATK and is Fire, Ice, and Lightning elemental. It increases every elemental magic type except Water and Holy. Is actually the best Rod weapon in the game*

Masemune has 104 ATK, 15% bonus to critical hit, casts Haste when used as an item, and grants the character First Strike property.

Rune Axe has 68 ATK, raises magic by 3, and consumes MP to deliver automatic Critical Hits.

Sage Staff has 50 ATK, casts Raise when used as an item, deals extra damage to undead and raises Holy elemental magic.

Sasuke's Katana has 96 ATK increases speed by 1 point, and has a 25% chance of blocking physical attacks. Is actually the best Ninja Blade in the game*

Yoichi's Bow has about 98 ATK, raises strength and speed by 3 points each, and raises the chance for a critical hit by 30%.

*When I say its the best weapon in the game it means it really is the weapon with the highest stats and ability. All of the other weapons may have a statistically better weapon that is obtainable through a sidequest or as a rare enemy drop. Many of these rare weapons also have certain properties that make them debatable better than the Sealed Weapon counterpart. Though some like the Giant's Axe or Artemis Bow are only statistically better than the Sealed Weapon and the extra powers of the Sealed Weapon may make them more desirable.