First off, I'm a newbie who's probably going to upgrade to Sonar X2.  I'm going to be recording soon and I'm going to be recording drums.  I know about the split notes to tracks cal and I was planning on using that for my drums because I'll be using BFD for my drums and I want to edit my drums before I bounce them to audio.  I would like to know the benefit or just the difference of recording using the multiple audio outs in BFD as opposed to using the split notes to track method?

You can edit and write all MIDI data on one track as each percussion instrument is differentiated by note.
In an acoustic space ie audio, each percussion instrument may need different fx and processing, eg a cymbal will need different fx and processing than a snare or  toms.
With Seperate audio tracks for each you are free to manipulate each one as you want or need.
Send them to busses then to group like sounds and then bus those busses to a drum master bus. Gives you incredible flexibility for later when you come to mix.

Mike is right but I would add that you can't mix drums recorded to a single track. With multiple tracks you can adjust pan and volume for each.

True you can do this with the MIDI but its better and more versatile with the audio.

Using BFD's internal routing just saves you some steps. There is no benefit to splitting a recorded MIDI track when you're using a synth like BFD. That would only be necessary if you're using separate synths for each instrument or separate MIDI channels for each instrument, such as with a drum sampler that doesn't support multiple audio outputs. Keeping all the drums in one MIDI track makes editing easier.

Forgive my ignorance but if I did it this way I would still be able to use the staff view and piano roll view?  I guess I'm a little hesitant to use the stereo outs because I'm not sure if I'll have the same flexibility for quantizing as I would if I kept it in midi?  

The MIDI track in isn't affected by the synths routing out.

You can use a single MIDI track for all of the drum line i.e. each drum, then route them out to their own audio outs for total individual control of each drum from simple like volume and pan to more complex such as EQ and Compression.

I'm with bitflipper in that with BFD2 there is really only one reason you might want to route it's channels in to sonars mixer and that would be to use effects that you can't find in BFD2. 
Having said that I think the effects and the mixer combined in BFD2 are one of it's strongest features but I do occasionally route a snare or something out if I can't find what I want in the BFD2 effects.
Also, although every single parameter within BFD2  can be automated (including all effects parameters) automation is a little easier when using other effects in sonar.


Steve

So you have more control over each drum.

You want to split the tracks to make it easier to sidechain the kick to the basslines, useful in dance mixes or heavy bass songs where you want the kick to come thru.

Midi - I've found the best way - for me - is to keep all drum midi in one track.  It makes it easier to edit than if drums were split into multiple midi tracks. 

As for the audio - I've found the best - for me - is to rout the drums into separate tracks in X1.  You certainly can do this within BFD, but doing it in X1 makes effects routing, sends, automation, etc. the same as other non-drum tracks.  So during mixing you're not having to open BFD's interface each time you want to make an adjustment.  You just stay in Sonar as you go back and forth between all the tracks. 

In summary - one midi track and multiple audio tracks.