Techy features keystone mods such as: 
Create (A steampunk-ish technology mod),
Thermal Series (Modern technology!),
Apotheosis (Complete overhaul of certain parts of minecraft),
Tinkers Construct (Custom tools!),
Computer Craft (Fully functioning computers based on the Lua coding language)

Techy's main goal is total automation, though, nothing's keeping you from doing what YOU want to do!. Frack oil! Explore! Hoard Resources! Make machines to help you hoard resources! Collect top tier gear!
You could even completely ignore the tech parts of the modpack, and just explore. It's whatever you want!
Lots of recipes for items are changed, so the gameplay of Techy is different from other modpacks, giving a unique experience.