EVA is going to be the longest run for upgrade, it has happened but it can take more than 8 years.
Taxes are 20 % flat but you can get back up to 10% tax refund depending how many days you were in Taiwan and your dependents.
Company accommodation is provided for single pilots at their complex in Nankan or housing allowances are paid for married ones.
The big difference is the chance to have 8 consecutive days off per month.
I don't know if you can request back to back in EVA plus adding annual leave days to each request.
You should visit both places in order to see which one suits better for you.