I absolutely can't stand the smell. It's a lot like skunk to me. It's sickening being around people who have smoked it.
The scents are caused by terpenes, the same chemicals that cause scent in other plants / produce. The interesting thing is cannabis has the genetic potential for producing many different terpenes commonly found in other plants! There are varieties that smell like pineapple, grapes, cookies, anise, vanilla, and banana.
There are also the varieties that smell like skunk, diesel, pine sol, bleach, etc. Those varieties became popular in the past as they coincided with strength and balance of THC / CBD. Sadly, young male smokers tend to prefer Skunky Indica types, so there's a lot of that out there and it may be the most recognizable of the cannabis odors.
Underneath these recognizable scents, there is a component of the odor that belongs to cannabis alone... but most people would find it inoffensive, and it doesn't have the power to linger.
Hemp comes in different varieties as well (as long as it's under 0.3% THC it is considered Hemp in the US), so it has a range of smells, but since that trait hasn't been selected for it can be very mixed.