From Sailor Moon Flash!
According to the SMF canon, each of the Great Crystals has its own individual power level. This isn't really useful information for anyone other than the really list-tendencied ones of us (like, for example, Cal), but on one-on-one levels in terms of raw power, it goes a little like this.
Individually, the Elementals pwn. One of them could take one of Our Heroes and smack them around like bitches, though depending on spheres they may or may not be breaking a sweat. Luckily for Our Heroes, the Elementals are incapable of working in concert; bring a friend and you're fine.
Speaking strictly of individuals, the Sapphire Crystal holds the most raw power, followed in descending order by the Golden, Ruby, and Silver Crystals. It is Serenity herself, not just her Starseed, that gives her such tremendous power; she has kind of a double booster.
The factions are powered accordingly, with each successive Captain controlling more power than the weaker members of the next higher-up faction. Thus, if we treat SMF like a game of Rock-Paper-Scissors, Coronis beats Kunzite beats Fighter beats Venus.
The important thing to remember is that objective power levels mean very little; there are more Lunars than anyone else, and they work together. Thus there will be two of them for every one of someone else, and they are capable of combination attacks that no other faction can match.
