This primarily depends on which game version you're playing, and what you intend to have the Drone do for you.
My memory of the vanilla version is rusty; it should have higher affix values to work with, but the AI should be wonky and Drone-oriented gear might be hard to find. 2038 and SP mods offer modded skills/gear, which might benefit the Drone more; the former also offers tweaked AI and Aggressive Mode, while the latter may offer a range of Drone-specific perks (eg perhaps indestructible Drone, like some mods have done for Elementals). The Steam version is rather tricky too; with Global's overreliance on weapon enhancements and minion caps the Drone was reduced to a solid tank with few support options, but Steam mods may be able to also make it a viable damage-dealer by fitting highly enhanced weapons on it.
The primary concern with most is usually its AI, which can be worked around to an extent by using homing/AoE guns or only swords for tank setups, but its overall performance will also depend on the game version in question. In many cases, it won't be that Drones are "terrible" so much as that they're not an *optimal* build focus or their performance is questionable for the investment.
