I've purchased C tickets to TPE on both EVA and CX. The EVA flight was an AA code-share so full miles and points. If you take EVA make sure you get the 777 and get the Premium Laurel seats. The 747s only have old style seats. If you take CX you will have to connect through HKG. The service on EVA was comparable to that on CX and is cheaper with no connections. Just make sure you get the code-share. EVA will credit to CO but not to NW.

I've used AA miles to get to TPE as well but not in C as it was completely booked. Had to go with F on AA to NRT and then down to TPE on EG. Home was on CX through NRT and then AA.