I wouldnt go anyway without my spiral guide and this holiday was no exception (Visited BC & Alberta indepentely during May/June 2003).
I converted to these guides some three years ago. I love the layout and siz of the guide - fits in your pocket nicely. It has a splashproof cover and the two flaps make great bookmarkers.
As for the contents, for this trip I found there was enough information for the larger tourist areas to point me in the right direction.
These guides are much easier to read than Lonely Planet if you want a good (but still comprehensive) overview.
I particuarly love the hints and tips for the 'must sees'.
Would highly recommend this guide and it has already been loaned to my friend for her forthcoming visit!!