Soul Eater's in-game description has two innacuracies: first, the area of effect is smaller than the described 14-ft radius (it's actually 7-ft, as the infobox states); and, second, the summoned skeletons are 1-Hit-Dice skeletons, not 3-Hit-Dice.
The skeletons carry a random weapon, have 24 hp, AC 7, THAC0 19, 1 attack per round and 15 STR as well as 9 in all other stats; and they have the same immunities and resistances as most other skeletons (undead resistances, 100% cold resistance, 50% slashing and piercing resistance). Finally, they can be controlled like regular summons and count towards the party's summon limit.
Moreover, the spell's area-of-effect 3d8 magic damage component is not party-friendly, but that can be considered as an advantage, due to the fact it's easy for a character to summon several weak creatures (for example, via Monster Summoning I) and use them as "sacrifice" to easily boost the caster's STR, DEX and CON up to 25 or close to it. And you'll still get skeletons to replace those other weak minions by doing that.
Description[]
| “ | This spell deals 3d8 magic damage to all living creatures within a 14-ft. radius. Any creatures that die as a result of this damage are obliterated, and their essence is transformed into a 3-Hit-Dice skeleton under control of the caster. Also, for each creature that dies in this manner, the caster receives a +1 bonus to Strength, Dexterity, and Constitution for 1 turn. Soul Eater has no effect on undead, constructs, and elemental creatures. | ” |