I can't attest to balancing or anything like that, but as a builder and appreciator of pretty things, world restore is one of my favorite things about Massive. The last server I frequented was awesome, until it died because the world was just so old that there was nothing left to explore or mine. New factions faced nearly insurmountable obstacles in locating land which hadn't been despoiled by miners, creepers (the server didn't feature Massive's block protection, either), or the corpses of old PVP bases; immense and obstinate cubes of cobblestone or or obsidian which loomed in silent, pugnacious defiance of all aesthetic sensibility.
There were more ruins to explore, certainly, but still most had been picked to the bone by looters. The 1000 blocks around spawn were a hideous, inhospitable wasteland of dirt huts, arbitrary pillars, ghost mines; their innards long stripped clean of all mineral resources, and replaced by the slavering, ravenous horde of the undead. To misstep in this early are was fatal, as those who survived the plummet into unforgiving darkness soon fell victim to ravenous monsters.
While I concede that it takes any world much time to reach this point, I just like permanently replenishing resources. My faction is located in Teled Methen. It's a lovely map, and a very easy place to build, thanks to its natural beauty, plentiful mountains, and a bounty of timber resources in all forms but jungle trees. It is a bitch to mine, though, because it does not follow normal Minecraft logic for mineral deposits. Cave systems are absent, and even individual hollows in the stone are rare. Patches of dirt and gravel are hundreds of blocks in volume, and can wear away the sturdiest of shovels without ceasing. Furthermore, they seem to border mineral veins only incidentally, meaning that most efficient way to mine is to dig straight down to y=10, pick a direction at random, and proceed in a straight line until you luck upon something shiny.
Thanks to world restore, I can compensate for the senseless nature of mining in Teled by jotting down the coordinates of any notable ore deposits I stumble upon, secure in the knowledge that when the world reboots, I need only revisit these locations for a sustainable supply of diamonds. With a few other miners in my faction, we can acquire a few stacks in hours. The more we mine, the more coordinates we collect, and the larger our supply becomes.
While the excitement of discovering an unlooted base and knowing yourself to be the first to claim its treasures can't be created by breaking 1000 blocks of stone, keeping simple records is more reliable and profitable over time. In summation, world restore is the shizznit, so far as I'm concerned.