They seem accustomed to use of the call button so I just summon them when I want anything. They usually come immediately. I have had mixed results on the quality of service - it is not uniform. Some flights have really happy attentive staff and others seem just so-so.

It is worth mentioning that most of their staff are living away from home in a housing camp in Doha from which they do all their non-stop flights. So, they are away from family in a weird (to them) land.

Also, watch them if there are any Qatari nationals in your cabin as they will typically fawn all over them, which I suppose is only fair.