I'm currently using it and loving it, since I am building a pretty big base at the moment and I need tons of stuff for it which is far more efficient to just mass-transmute. Allows you to get some serious stuff done if you have big plans, but many people see it as 'cheaty' since you can just farm basic items and ultimately derive diamonds (or better) from them for next to nothing. This mod lets you transmute most vanilla items(and items crafted from vanilla source materials) into other vanilla stuff using EMC. ProjectE: Questionable if you see yourself as 'Hardcore' and/or have lots of time or enjoyment involved in mining. Allows you to store millions of items in a searchable network and also enables you to automatically craft stuff (and automatically crafts the stuff you need for your stuff, if set up properly). Refined Storage: A must if you want a simple computer-based mod. Good for getting a power grid up and stable.

Fairly simple to use and craft stuff, but resource (iron, redstone) intensive. Thermal Expansion: Generally a solid RF mod. I'm pretty new here myself, but I will share what I've found:

Best tech mods for minecraft