We flew YVR-TPE earlier this year on the BR codeshare, in business class. We had a similar experience with seat assignment, and we were unable to book meals in advance which BR allows, because we could not find a way to figure out the BR locator.

Service was quite nice, but seats are not great. Placing a large pillow on the footrest improves the situation considerably however.

On the way back, when checking in we asked for changing our seats from ours in one of the standard rows assigned to AC to the front cabin which is more private. Flight was nowhere near full in front and we ended up in the first row.

Meals were good but simple. Wines were significantly better than AC or even LH. Puts AC to shame.

Overall I would say our experience was positive. We would fly them again.