I haven't really kept up with Browning since around 1994. Back then I was working for a dealer who was contracted with Browning as a certified dealer. I believe it was between 1992 and 1994 when Browning introduced the BOSS system, but back then it was offered on the A-Both II. I wasn't aware they were now only offering it on the X-Bolt, which didn't exist back then.
I can't advise you on the X-Bolt specifically, but I got behind a good number of the A-B II's with the Balistic Optimized Shooting System, or BOSS as it were. I don't recall ever having shot any factory ammunition though, only my reloads. The BOSS in my opinion is a very effective accuracy enhancing device though. It allows you to tune the harmonics of the barrel to the round, rather than having to tune the harmonics of the round to the barrel. I remember my first experience with one was a stainless AB-II chambered in .270 win.. I printed 5 rounds without making any adjustment and got about a .600" group. And on the second group, following a quick adjustment to the BOSS, I printed an honest .321" group, only .044" from being perfect. In all honesty, I think the BOSS is a proven system, and I'm really not a Browning fan.
GS