Superior Drummer is better if you like to do a lot of tweaking and
playing with the settings (which you can also do in AD)
I, personally, use AD as my GO TO....I can get a great sound
relatively quickly, and get on with my work....the ADpaks
are far less expensive then those of SD....and AD loads
relatively quickly and is less taxing the system...The downside
of AD is that they don't have anywhere near the Addons that
SD does....
That being said...it's down to personal preference...and how
much you really want to do...