The buses are new, modern and air-conditioned. They are used mostly by (male) foreign workers. Qataris and expats who are professionals drive their own cars.
It can also be very hot to wait outdoors especially during Summer and cold during winter. Supposedly air-conditioned bus shelters are planned. So far, they are like the ones we have back home in S’pore. There are quite a few still without the shelter but only has a green pole-like structure with the bus route info on it.
Could someone comment on the fares ?
I heard pickpocketing happens on these buses. Not surprising.
Here’s a link to a pdf file showing the bus routes :
Share Lah Don't Shy ! 
Gud Blog. I need some more info about Limousine services Qatar.