The KRG has a lot more modularity to it, so it's a better stock to "grow into". If you decide to get a tripod or an ARCA/RRS rail to mount to a tripod, it's an easy and available addition to the KRG Bravo. You can add weight kits and weighted LOP spacers if you want to increase the weight of the chassis. If you want a spigot mount, you can add it. NV bridge? Bag rider? flush cup mounts? Picatinny rails? It's all readily available for the Bravo. If you want to add any of the above to the B&C, it's a lot more work and unless you have the skills and tools yourself, you will be sending it off to a gunsmith for time and $ to get it done.
If it was me, I would take the Bravo hands down over the B&C. When I first started in the sport, I had a GAP rifle in a McMillan stock. As I shot more and more and started to learn what I wanted in a rifle, the $ and time to modify the stock to add what I wanted (bottom rail, flush cups in specific spots, etc) was getting pretty annoying. As great of a product the McM is, it's not modular or easily upgrade-able. I've since swapped over to chassis's, as they grow with me as my needs and preferences change. It was going to cost way too much to modify the stock to my liking as I found out what my preferences were.
Also, keep in mind you will also have to get a DBM for your B&C stock, so that's an additional $100+ and gunsmith installation. KRG Bravo chassis has DBM built in to the chassis. To answer your question on the ergonomics, I think the ergonomics of the KRG Bravo are excellent. One thing to keep in mind is that it is a light chassis, so if you put a long heavy barrel on it, it will be front heavy.