Ity was our first time to visit Taipei so we thought of getting this transfer to save us the trouble of looking for a ride when we land. We were expecting someone to meet us at the appointed time and location at Taipei location but there was none. So we texted the local contact and they claimed the person was there. We walked around again and read all the signs that were being held by those who were meeting other guests but we did not see our name. To make a long story short, the company eventually had us picked up curbside by someone who did not understand English after more than an hour of texting back and forth after our appointed time.
There are plenty of taxis just a short walking distance from the terminal exits so you don't really need to book a transfer from Taipei airport.