Much more often and reliable than Canada for sure. If you live on the fringes of societ-I mean just outside of the MRT but a bit too far to walk, they may be your only option. I do use them in the middle of Taipei as well if you want to take a shortcut without going all…the…way…around on the MRT, they can save time, for example, going between the Xinyi/Xiangshan area to Songshan or the 947 bus from Danshui to Banciao.
In Twinbei(hoping it catches on), 900 series buses, excluding 981-985 are local buses that use the highway to skip over large sections, like 909 to Xindian, 939 from Xinyi to Sansia, and 947, banciao to Danshui. They can be real time savers if you use them right. 986 is a cheap way to get to the Taoyuan Airport via highway as well.
Coloured buses are special MRT shuttles. They’re usually short, but they ALWAYS go to an MRT station in one way or another. Easy to start with these if learning the buses cause if you get lost, at least you can get off at an MRT station and find your way.
House prices near the MRT can be rather high and I refuse to live in Gongyus, so I choose to go a bit further to save some money.
@Incubus mentioned the apps. There are also the websites as well.
New Taipei eBus
Keelung eBus (Independent System)
Yilan eBus (Independent System)
Taoyuan eBus (Independent System)
Anyone else want to add the websites, feel free to post them too.
Hope this helps!