I notice when controlling a softsynth I can choose NRPN or CC.  Is there a difference between the 2 and should I use one or the other?
 
Thanks!

NRPN requires more data and is sometimes slower to be processed. Not actually sure if the latter goes for softsynths. CC#s directly access a parameter so unless you have some reason to pick NRPN I would usually go with that.

to add to that...  how about automation lanes to control softsynths?  I see that doesn't even work off of CC or NRPN.  I would like to know the pros and cons of each.  Thank you!

It all depends on what you mean by "controlling a softsynth". If you're programming parts and you need to modify a parameter over time then an automation lane is convenient. If you want to twist a knob you'll need a controller with an assignable knob. CC#s will be much easier to set up than NRPN in that case (if the controller supports sending NRPN data at all).

There is technically no difference between an NRPN and a CC. The difference is that NRPNs have no definition in the MIDI spec. They are there to allow synth vendors to extend the standard spec by adding their own product-specific commands. This means they usually include some additional data after the command byte, whereas CCs generally add only a single byte, or none at all. With each NRPN command requiring 2 to 3 times as many bits as a CC, I'd be reluctant to use them for continuous automation, although in practice that overhead might not be significant.
 
So why select one over the other when both options are available? Probably because the NRPN offers more control, such as delay and feedback parameters to a chorus effect rather than just the chorus mix that CC#93 provides. Why not use them? Because they are instrument/effect-specific, which will make it difficult to substitute another synth or effect in an existing track.

One other thing to be mindful of with NRPNs is that sending these events to some synths silences those synths.  The only way to recover is to reload that synth.  I know Rapture Pro does this.

thank you all for the replies.   What about automation lanes or CC data?   pros/cons?

NRPNs silence all the Cakewalk sfz engine synths. To prevent this from happening, check the "Do not intercept NRPNs" setting in their plug-in properties

Same answer as the last time you asked in the fb group on January 5th, Adam Lewis.

Wow. That's pretty bad behavior. Good to know, thanks Scook and Promidi.

To the OP, CC#s can be recorded from most generic midi controllers so they are a good choice if you have a physical knob or slider you want to use. Automation lanes are more convenient when you want to draw precise values or when you want to edit sections later on. They also let you select parameters more easily because they're named automatically.

It would be easier to give more specific advice if you gave an example of what you want to do.