DOM. The ADAT PCI card can in almost no way replace a BRC. Primarily, the ADAT PCI card is used to transfer ADAT tracks to the hard drive for editing.
The BRC is used to control a number of features in multiple ADAT machine configuration. It is so expensive because it is a controller that works flawlessly for it's intended use, which is very different than the ADAT card.
I have the ADAT card, and wish I could get my money back for it. It simply is a pain in the ass to get to work right, and it requires a lot of work, and a very strong DAW to even transfer two tracks at a time. I have heard of not one person who has easily installed one and had it working right out of the box. Most people have stated that they spent many hours waiting for tech support and several occasions to get the card to function properly at all. Basically, it is a nightmare.
It is not like "having another ADAT" because you have to have some other D/A converter to hear your tracks once they are on the hard drive. It does not have A/D/A converters at all on the card. Also, it does not sync with any other soundcard that I know off. Also, it does not support any midi functions, or as far as I know, sync to midi in any way.
I am not sure what that card actually does well, except transfer your ADAT tracks to the hard drive. At $300, it is twice the price it should be in my opinion, considering the fact that you still will need another soundcard that supports 48kHz files to actually hear them.
Other companies are making card that have ADAT I/O as well as two A/D/A converters on them, and are usually around the $500-600 price range. A much better deal considering that you can actually hear the ADAT tracks that you transfered. I would advice looking into them. I just don't think the ADAT PCI card will provide you with the features that you may want from it.
Ed