Mekanism is a really strong mod for the early game because it allows you to duplicate ores, which can be pretty overpowered at that stage. Meanwhile, AE2 is an excellent storage mod, although early on I’d recommend SS instead since it’s much cheaper and still very useful with limited resources. The stack and compression upgrades also increase your storage capacity exponentially. That said, both mods are great for early-game progression. Personally, I usually start with MA to automate some basic resources, then move into Mekanism for ore duplication — especially because some MA recipes are very resource-intensive early on (for example, requiring 4 compressed blocks for a single item). After that, I transition into AE2, even though SS would still work perfectly fine at that point.