Since AH2 I have been loitering up at around 20K. Mainly because my framerates are playable up there. Most of the above mentioned planes do well at altitude. Just learn one and stick with it for a while. Doesnt matter if its the best or not...most of the planes have an area that they excel at...exploit those attributes and you will be succesfull.
There are lots of good fights above 20K...the guys who dont run make it worth the wait.
RHIN0