Not been yet, but according to a friend who used to live in Calgary I'd say sddsddean's reply is a very true reflection.
Living costs tend to be higher than much of Canada, although Calgary is catching up now. It's a lot more than eastern Canada, but less than the UK generally.
Weather is kindof on the slightly wetter side, but very little snow. Tends to be a lot dryer air than the UK (and eastern Canada), but it doesn't have LA type temperatures as a rule.
Safety - one thing you'll find about Canada is you can walk anywhere and not think about it. For example, I walked through the roughest part of Calgary holding an iPod and digi camera and people just smiled.
Everything else....well from what I hear, if you can afford the houses it's a very nice place to live. Oh and if you're coming from the UK, you can swap your driving licence in BC for a Canadian one without even taking an eye test.