I just tell you my surfing experience after 8 months staying in Taiwan.
I landed in Taiwan july 2011 and went straight to Dulan, Taidong county. I spent one month there. I never surfed Donghe river mouth, which is the most famous and crowded spot there, rather I went exploring some bays down south and everyday there is some surf: sometimes knee high, more suitable for longboard, and overhead on typhoon swell. I was most of the time alone surfing between 5:30 and 8:00 am. Early morning, even on windy day, early morning it's glassy over there, than wind rises up after 8 am.
I met a guy from San Diego, english teacher in Taidong/Taidong that was enthusiastic of the surf there.
Mid august 2011 I move to Taipei. Unfortunately. The surf here it's not that good. Moving from Baishanwan (really north shore) to Yilan County (East coast) you have surf almost everyday, on winter time. But most of the time it's windy, choppy, sometimes messy, some others just too big.
I just observed that summertime it's not that consistent but better quality when the swell comes (groundswell from typhoon), wintertime it's more consistent (windswell from NE) but quality wave is lower. And I am speaking of Yilan County. Just checking the forecast (MSW website), it seems the best surf in Taiwan it's between Hualian and Taidong. Even on very windy day on Yilan County and North shore, that area it's most of the time not that windy.
One more thing: weather in Taipei sucks. I think everybody agree unless there is some frog between them. It's rainy, damned rainy on wintertime. Summer it's damned humid and hot.
If you want to surf and don't care of bustling nightlife, shopping, experience international restaurant and so on.... get a job in Hualian or Taidong area, it's my advice.
As I told you I have just 8 months experience in Taiwan, then, some surfer more experienced than me can tell you better how surf is.