It's now referred to as Brigade F&F because Regimental F&F came out a few years back. Having both sets gives you the right tools for different jobs - big battles or smaller actions. They are obviously similar, but RF&F does have a different feel. I never played a lot of the original brigade F&F, but enjoyed the games of that (and V&B) much more than when I tried JR, which seemed to require the same level of rules dedication as playing Empire in Napoleonics. I got into the ACW myself about when RF&F came out, so have been very happy with the new releases. I consider myself a "history first" gamer, but I prefer rules that emphasize the importance of player decisions, and then let them see them succeed or unravel as forces are ground down, making it difficult to react. F&F does that very well (although we incorporate simple written orders to further complicate things).
If you want simpler regimental rules, Rank & File by Crusader Games is excellent, and the old classic Volley & Bayonet is a simpler approach to brigade level games. With some knowledge of the period they can be guided to give a good game.
Cheers,
Christopher