Quality of taxi's are good since most of them are relatively new.

Yes, they use meters, , u have to pay what is fixed. There is no bartering required unless u r driving in an illegal taxi.

There is only one brand in Qatar so far, which is called KARWA

Yes taxis are hard to find, have no experience with radio despatched taxis as I have my own car but heard people complaining that they are usually late or never arrive at all.

so long and happy taxi...ing?