This is the Go and UP Express station at Weston Road, near Jane St. Both GO and UP services operate from here with two separate platforms for each train. The station was recently renovated and updated for the UP Express, which is now much less expensive than before. I take the UP downtown and back every day now because the price dropped enough to make it competitive with other, lesser transit options. It's frequent (every 15 minutes), costs $5.02 to get downtown, has ample seating, and free Wifi!
The new station platforms have an indoor area that is heated in winter and lots of Presto tap pads so that you can tap on and off before and after your journey. Just remember to use the same type of tap pad at the start and end of your trip. There are silver ones for airport passengers and green ones for regular GO passengers. You can use the green ones on the UP Express as long as you're not going to the airport. Careful: if you tap a silver one at the start of your trip and a green one at the end (or vice versa) you'll be charged a really high maximum fare!
The station also now has two parking lots with free parking and some reserved parking. Even so, this station is one star short of perfect because it needs even more parking. There are some mornings where, even when I arrive really early, there are not enough parking spots. That said, that's a minor issue. The new station is beautiful and the UP Express is fantastic!