I think people are using session drummer 3 but the more serious they become about their drums then the more likely they are to start looking at what else is out there.
Here's my take, session drummer 3 is Ok but with the exception of EZdrummer (which is better but not by much IMHO)
it is very (and I mean very) limited compared to almost everything else out there.
The sound set is ok and is improved hugely by adding some of the Platinum Samples expansion kits but you have very limited control and tweak-ability.
If control isn't your thing and you ust want to use drums that sound like the drums you hear on your favourite records and you don't want to spend time creating a drum sound that is truly of you own making, there are still far better options out there.
Steve Slate and Addictive Drums to name but two.
Of course it means spending more money, and session drummer though not truly being free (it is included in the cost of sonar X2)
is apart of the whole package. The reason these drum threads occur so often and the reason people seem to care so much about drums is IMO because we ALL use drums in our music no matter what style or genre. WE don't ALL use synhs or real guitars and bass. we don't ALL want great orchestral libraries but we do ALL want great and realistic sounding drums.
Although opinions seem to differ greatly on what in considered to be, "realistic"
Stve