We've used CANSPEC on two different occassions. First when we purchased our own home in 2000 by Tim Purtill.
It was a detailed, straightforward and simple to understand report.
The second time, Tim already retired or moved on to teaching seminars on home inspection (not exactly sure) however the person who did the inspection on our prospective investment property did a GREAT job too. Also, they were available to do the inspection at a moment's notice, and were respectful and patient with us.
With houses, you don't know what's hiding in the dark corners :-) so I highly recomment hiring a real professional company like Canspec.