I am pretty new the forum, but not new to gravel.
Sorry for resurrecting this old thread, but in reality there is very little on this forum in regards to B-RAD, and not that much more elsewhere on the web. There are a couple good Youtube videos, so its not like there is no info out there.
I am preparing for a 370 (310 on paper) charity ride from Pittsburg to DC this fall, and looking for options to carry gear/water, and was already aware of the B-RAD system. So recently I went to my LBS and ordered the 3 and 4 to put on my '15 Boone Disc 5.
The hardware itself is very well made, spacers and a foam pad for each bracket, screws, ziptie, and black WT sticker. The B-RAD brackets are precision machined aluminum, and pretty stiff! So the design uses the channel to allow you to slide the bracket up or down in the channel and then lock it down intop lace. From there, the holes to tie your waterbottle down are in fixed locations, so the micro adjustments are in the bracket itself depending on where you tighten it to the frame.
I installed the 3 on the seat tube and the 4 on the downtube. I currently don't have anything else on them, so I took the 4 off until I actually figure out my setup as far as what and where. My original plan was to mount a custom built bluetooth speaker way in the front of the triangle because I am going to have a lot of solo rides...music will be nice. On the 3, I plan on fabricating a strap to hold a tube, bike tool and levers below the water bottle.
So far, i can say that if you're going to try to maximize the space in your front triangle, you should probably look at side loading bottle cages options to fit your needs.
Now in regards to full suspension MTBs, I believe you could actually make this work assuming you have space to mount a bottle. There are two notches in the bracket to allow you to strap it to the downtube (or under the top tube) with zipties if you need to. I am actually pretty lucky that all of my past/present MTBs came with the ability to mount a cage in the front triangle, where friends with Yetis struggle. I ride an Ibis Ripley LS which has a waterbottle cage braze-ons and aftermarket Blackburn packs to wedge in the front. I also have a Kona Honzo ST setup geared but was SS, but the hub was struggling being set up SS. It has 3 braze-ons in the front triangle for bike packing I believe.
I don't have any pictures as of yet, but if there is interest, and when I am further along with this project, I can/will get some pictures out with my setup.
Overall, I believe if this is a solution that you're considering because you need it, just buy it, the brackets at least. The products are very high quality. As for the strap accessory, I believe I can build something that will work just as good and not cost another $25. I believe its price about $10 too expensive IMO.