There is not much difference between end results if you design using CISC or AISC.
AISC follows different stability curve ( I think curve 2 or 3 )for columns design while CISC is more inclined to Euro codes in following different curves, so the formulas and results vary slightly.
Also, as far as I know, "Gerber beam systems" is common in Canada while it is not much popular in US. Although there is a Canadian publication for these type of beam system, but is only available thru AISC.
For bracing stability and design you need to refer to AISC for good explanations while for HSS design there is more information available in CISC.
In the end, it all comes down to which code you are allowed to use in a particular job. The end results vary slightly.
The best way to find out is do design using both the codes and see the difference yourself.