Paul,
I can tell you that I have had Preston's Guide for the last 8 months and I have yet to find a reliable answer to anyone's questions on this board using it.
I am very disappointed in Preston's. I'm not saying it is not useful, just that it has not been very useful to me since I've had it. Maybe combined with Carlson's Dunlop (sp) they may make a great team.
I will be buying Carlson's in the near future as soon as I do a few more inspections to pay for it along with all the other toys I want to buy.
