I have very limited experience, but for what it is worth....
We had Shaw's high speed lite, When we lived in Vancouver's West End, which is a very densely populated area. Starting at 4pm, and progressively getting worse for a couple of hours, the speed of the service got noticeably slower and slower. My understanding is that Shaw uses a node system ie a number of subscribers in an area share a node. When they all come home and start surfing, service speed suffers.
We have an ADSL connection on a gulf island now. It is a local provider, but they are repackaging Telus ADSL connections. In the 5 or 6 years I think we have two problems that lasted more than a few minutes. One of the times was when Telus added a considerable number of new customers to their system, but didn't add the connections to get the traffic off the island. That caused sporadic slowdowns and hard to reach servers for a couple of days.
Overall I prefer the ADSL, despite the occasional glitch. The Shaw service affected every week day.
I have heard that Shaw Tech support is better than Telus. And I know people who have switched to Shaw for that reason. These people had serious internet needs however (servers at home, etc)
Hope this helps.
Welcome to BC. Don't wear cotton socks in the rain, you'll be a lot happier.