Veteran Packs, they cost 20,000 credits and give a guaranteed Uncommon or better,the rest are common. Those give common weapon mods more reliably than 4 Recruit packs.
Premium Spectre Packs cost 98,000 credits and are good for 2 Rares or better with the occasional Uncommon. You will likely never max out your Common weapon modifications with Premium Spectre Packs.
