It also has a noticeable chemical smell to it, but it went away after a couple days. Its well worth the smell IMO.Early on I used 303 on the outside, but now (6 yrs later) I don't. The plastic panels don't really need anything. Plus, if you apply it too heavily, you get streaking after it rains. It's kind of expensive, so I don't slop it around.
Now I mostly use 303 to clean and lubricate the door seals (and wiper blades).
Occasionally I use it on the interior panels - but beware that it leaves a slick coating, so use with caution on the surfaces like the steering wheel.
I also use it periodically on an inflatable boat and dry suit cuffs.