I've used it a lot of different ways. I found it particularly useful for bringing acidized files into cubase from Acid Pro ... since Acid Pro is a very simple easy to use platform to arrange, pitch and tempo shift and chop in ... if you have the acidized files.

To bring in multi-tracks audio from Reason, you have to make sure the different devices are individually (or in two individual stereo tracks) routed to the Reason 'Hardware Device,' that sits at the top of the rack. Normally there are is only a single stereo pair routed from the mixer. There are actually 16 stereo pairs available.

In Cubase anyway (and I'm sure something similar in Nuendo) you also have to open the 'devices' menu and select 'Reason Rewire.' Once that box pops up it will show all the possible Reason inputs deactivated. Just select/ activate as many as you plan to use and now you can stream up to 16 separate stereo audio channels into your DAW in perfect sync. This turns Reason into a powerful and flexible 'softsynth.' With all of Reason's routing capabilities you can add chains with effects, etc., route them to a mixer in the rack and then route that to one of the 16 stereo pairs.

With respect to midi, you can either sequence your midi in Reason or stream midi from your DAW to the instruments in Reason.

Reason itself can only run as a 'slave' under rewire, but most DAWs can be either slave or master. You can only have one master, i.e., the first DAW you open, but you can have more than one slave.

Were BIAB at least a rewire 'slave,' you could route the midi into Cubase, for example, then route it out from Cubase to Reason and route the Audio back in. Imagine the possibilities! You could then do all you mixing using what ever effects ... including external hardware ... through the Cubase mixer.

Of course you could also route the BIAB 'slaved' midi out to synth hardware through Cubase ... or any combination that you want.

Were BIAB to implement rewire, virtually every serious DAW user would immediately want to get it for the utility of it's auto arranging features.

Prado