Every block mined with the cutter will cost 500 EU, and with a storage capacity of 10,000 EU. An EU storage device is highly recommended since you can only mine 20 blocks with the tool before running out.
The cost of this tool is 3 diamonds, 2 Titanium Ingot, an Electronic Circuit, and an RE-Battery. You can replace the Electronic Circuit in the recipe with a Receiver Circuit, Medium Circuit Board, Redstone Golden Chipset, Iron OR Gate, Iron AND Gate, Autarchic Gate, Controller Circuit, Bronze Electron Tube or Iron Electron Tube.
This tool is very useful for mining out Diamond Ore, Lapis Lazuli Ore, Redstone Ore, Coal Ore, Ruby Ore, Sapphire Ore, Emerald Ore and Iridium Ore. It's more effective to mine these ores out with the Rock Cutter than a normal pickaxe or drill because if put the ores in a Macerator or Rotary Macerator, you can get double the usual yield for these ores. The yield is even higher when using an Industrial Grinder or in some cases a Grinder.
Rock cutter can be enchanted on an anvil with a book, since it already has Silk Touch, it'd be wise to enchant it with efficiency to offset its slowness. However, care must be taken to not drain all the energy when using an enchanted rock cutter as that results the loss of enchantments.
Do note that diamond drills (both regular and advanced) use considerably less power than the rock cutter and can also be enchanted with silk touch via enchantment books, but diamond drills are more expensive to make and silk touch enchantment books are hard to come across.
Recipe note: in Gregtech 2.03b (FTB BETA A pack) you can use Steel instead of Titanium.
This spotlight shows the Rock Cutter powered by a Lithium Lappack.