Aight, well I played last night with this spell. Unfortunately I was unable to use War Weaver, because the DM doesn't like pre-req combos like that apparantly... (Unfortunately I won't be playing that game anymore, at least for a few months, cuz he was caught breaking parol and got jail time. Oh well.)
But on the topic subject, Snake's Swiftness I found to be WAY more useful than fireball with the amount of players in the party. 6 other combatants besides myself, all with a melee or ranged attack. If it werent for Snakes Swiftness Mass, we probably would have lost the fight, cuz I popped it twice. (One player and a horse got eaten, by the plant things we were fighting; luckily they survived because of the spell, allowing everyone to get their final attack.)
So in my opinion, versus a random amount of enemies, Fireball falls prone to a more powerful spell such as Snake's Swiftness, Mass. Fireball is great versus an incoming group of known enemies and the like, but dangerous in combat.