GregTech on its own comes with a huge tech tree using the EU system and the other technology based mods will open up while you are progressing through the tiers. If you are fan of expert mode packs and want to take it to the next level this pack will be your friend!
Later on you will have to visit other planets and dimensions to gather important ressources and fight mighty bosses to channel their magical power. Starting in the stone age you will barely be able to survive until you get your first steam machines and eventually reach electricity. To reach this goal GT New Horizons is using the tiers (basically ages of technology) from GregTech and allocates content of other mods to a fitting point within the progression. The main intentions of the pack are a long lasting experience and tying mods together in a progressive fashion, making it feel more like a single game than a compilation of mods thrown together. We are talking about thousands of recipe tweaks, a massive questbook with custom reward system, unique world generation, custom mods coded for the pack, custom Thauminomicon pages, and many more.
Over 3 years of developement (and still going) have formed a balance and refinement that only a handful of packs can keep up with. You are looking at a big progressive kitchensink pack for Minecraft 1.7.10 balanced around the mod GregTech. GTNH Large Modpack with every recipe Gregified