well there r number of reasons why Mehran is so popular, in my opinion!
1- Same shape for past 17years which means, even your 6 years old Mehran doesnt looks OLD!!! - a big advantage!
2- CHEAPEST SPARE PARTS!
3- Spare Parts available EVERYWHERE!!! and that means even smallest of the towns!
4- Mechanics even in some village totally understand the car, its engine, and its construction.
5- More spacious than other cars in its class, like, Cuore, Chery QQ, Chevy Exclusive or Joy.
6- Can carry more loads because of "KAMAANI" based rear-suspension, a big advantage for KAROBARI PEOPLE who sometimes use it as a small LOADER!.
7- Small size enables it to get into GALLI MUHALLAZ easily!!! a big advantage! (but cuore etc is also good at it).
8- Biggest pro! ITS ALMOST LIKE A CHEQUE! u can sell it at any showroom within an hour. Dealers are always ready to buy it with LOWEST DEPRECIATION u can get!!!
9- Some may not agree, but its pick-up is amazing because of a very good body-weight/engine power ratio! and it sometimes exceeds that of other competitors in its class.
these r few, with number 2,3,4 n 8 being most important.