Used Onur Air on internal flights in Turkey last week - Istanbul - Bodrum and return. They were very good in all respects. I don't speak any Turkish except the usual pleasantries, so I was a little worried about how it would go.
I had booked on their internet site, so just presented my confirmation number at Istanbul domestic check-in and they sorted our tickets and showed us where the gate/security was. Very helpful. Flights were on time both ways.
Onur were an example to the likes of Easyjet and Ryanair, they offered boiled sweets once everyone was seated, then during the flight offered tea, coffee, soft drinks(limited choice but it was free) and cake or crackers, all with the usual politeness that we love about Turkish people.
I've also used them last year from Galsgow - Bodrum & return and they were good then also. Service was similar to above. As someone else said take a book as they don't have any entertainment.