Sun Life isn't even that bad, it's not a nice looking development, but I don't think it's any worse than any other smaller 70' - 80's complex in Calgary. At worst, Sun Life is like the Telus tower beside it, just boring and not really worth noting. Calgary (and every other city) has far uglier towers than these.
My vote for the ugliest tower in Downtown Calgary
https://www.google.ca/maps/@51.04456...2!8i6656?hl=en