Air Canada and Canadian have recently been great on my miles on their flights. It is their partners that have given/and continue (for Canadian) to give me grief. Star Alliance partners have not always been up to snuff either. On my last trip to Europe, I was credited only 2 of 4 flights on SAS and Lufthansa but Air Canada quickly credited the other 2 when notified.
Air France has a 50:50 record. When it is computerized (i.e. Europe) no problem, when it is manual (ie. Africa) I always have to write.