Rocket or waste oil?

Hi all,
I've been researching and considering different (better) options for a shop heater. I'm new here and thought I'd ask "those in the know".
I like waste oil because the fuel is free, it's hot, no smoke or smell and it's cheap and quick to build. On the flip-side, they're very noisy, dirty oil can clog, and there is potential to use more oil than I can find.
The rocket is also cheap to build and cheap to operate (I have plenty of surplus wood, now). I think it would make enough heat for my 30x40 shop and would probably take less space. I like the idea of burning scrap wood without having to cut it down to "wood-stove size". I have several potential "tanks" (water heater, 250 gal oil tank, 55 gal drum, etc). The down-side: I think the rocket would be a pain to light and building may take more trial and error. Also, I have some large chunks I'd have to split the snot out of, to make it fit.
Now, what does everyone else have to say. Am I way off base? Is there more I should know about either heater?

By waste oil do you mean motor oil?  Does burning the waste oil, with the additives have any potential harmful effects?

I have no idea, just wonder.

Waste oil might potentially be recycled, or (if it's vegetable oil) up-cycled into motor fuel.

Liquid fuels can, in some circumstances, be more of a fire hazard.

Do both.  I've retro-fitted drip burners into conventional wood stoves and it worked great. You start the fire with wood and then open a needle valve to start the oil drip. I used veggie oil that was too hydrogenated to easily make biodiesel from. The drip burner is gravity fed and designed after a ceramic kiln burner with stepped plates.

Ernie has mentioned that he used an oil drip in a rocket stove.  haven't heard any more detail than that.