Guys please share experience.

I use both to advertise so u can find same vehicle in both ad platform. It just to be careful when selecting your choice of vehicle, check for rust, condition of body, engine, transmission, aircondition, electrical/wiring and interior. I will advise u go with a professional automobile mechanic not a local one to check before u buy.

I also want to know cos I'm ready to buy one now and there have been many stories of how Car sellers are fraudulent and even how some buyers are fake, so it makes me lack confidence in the system.
Where exactly is/are reliable?

You can actually buy a good car from jiji and nairaland,
On jiji
Choose location closer to you, search for the car you want, and when you see what you want, call the seller to confirm the car is still available, actually try and make video calls with the sell, when you confirm the car is still available, look for a competent mechanic you'll pay to check the car when you go for inspection and buying, before buying confirm the documents with computer global,
this tips will save lot of stress.

Telling you from experience, I traveled to inspect a non existing car. People sef, after then I learned