The Star has a comparison of the UPX and airport express trains around the world. The UP Express, which will open this spring, will cost about $30 each way.
In short, the Star finds that the UPX compares favourably with the trains that Metrolinx would like it compared to (in Tokyo, Oslo, and London), but unfavourably to other trains in Vancouver, Chicago, New York, and Madrid.
The comments are (for a change) worth reading. My favourite:
What these comparisons show is that UP Express is the worst of both worlds. It’s not especially fast, thanks to the two intermediate stops and the fact that diesel trains accelerate much more slowly than electrics. But the fares are being set at a premium level, as if it were a genuine express like the trains at Heathrow or Arlanda.