My first question is, assuming you have used session drummer 3 that comes with sonar, what didn't you like about it ?
Was it the sounds? lack of velocity layers and articulations? I guess you need to know what you want first but then you also need to know what's out there
I think the first two questions you might want to ask your self (or that I would ask you) is...
A) do you just want drums that sound mixed and ready to go that you can throw in to your music in the hope that they'll work ?
Or B) would you prefer to have complete control of how you want to shape them into something more original and that you can truly call your own and do you want to LEARN to MIX drums.
If the answer is A, then superior drummer and BFD2 might be a bit over the top for you and you may find the steep learning curve a bit overwhelming and give up.
I would then suggest either BFD Eco (BFD2's little brother) or EZdrummer which is superior drummers little brother.
IMHO BFD Eco sounds much better, is more versatile than EZdrummer and comes with a much better mixer and more and better
effects. It's a shame you only just posted this as Eco was on sale for $29 until the end of June but is back up to $99 for now.
EZdrummer is the simpler of the two and IMHO very similar to session drummer 3, it's clearly the better of the two but not by much.
If the answer is B) then both BFD2 and superior drummer work very well with sonar.
There is also Addictive drums which I would put just behind both superior drummer and BFD2 as the sample quality is compressed
and a lower bit rate and it sounds like it too. But to it's credit I was so impressed with the range of presets in different styles and genres that came with addictive drums and the whole program is less than 2GB.
My personal choice has always been BFD2 & BFD Eco.
Of course, I am biased as I'm a beta tester for FXpansion but I was a customer first and became a beta tester because I love their product and their ethos and to my ears their samples sound bigger and warmer and lovelier.
I much prefer their mixer and you get a very comprehensive range of very high end effects (not just your vanilla compressor eq and reverb)
The idea behind BFD2 (and superior drummer) is to let you be the engineer in your own drums studio. You have all the raw samples of very well recorded drums and all the control that you would have in a recording studio so you can tweak away till the cows come home.
You can get a demo of BFD2 from fxpansion to try out for your self. You'll need to register with them in order to download it.
Steve
P.S. You may also find that your machine lacks the power that is required for both BFD2 and superior drummer.