Pros
If you're in IT, there's lots of different areas that deal with lots of different kinds of technologies that you wouldn't see at a small company. There's also decent opportunity for advancement, if you're a go-getter (and a bit patient).
Cons
Opportunities for advancement are pretty much only available if you go after them and know the right people. HR is a mess. TELUS is not the kind of place where you can just do a good job with your current position and get promoted. The other catch is that the only way to get a real raise with TELUS is to switch jobs within the company, so in order to advance you need to be a go-getter but you also need to be willing to move around a fair bit. This is not necessary a bad thing for everyone - depends on the kind of person you are.