I think the SS looks better than the brass
Well, I think it depends on the color of your horse. If you're cursed (I mean, "blessed") with a red horse like I am, brass looks pretty darn good! *LOL* But oy, the work!
Definitely go for the sliding back band. I don't have any problem continuing to use my traditional fixed tug Camptown saddle but the sliding backband has been great on all the sloping roadsides I drive on and it's really sort of fun the way my Hyperbike now slides through highspeed turns. Kody's also had fewer back problems this year but I can't say if it's the sliding backband, the stifle surgery, the new warmup routine, the stretching routine, or more likely some combination of all of the above.
Benefits: When you're driving on level ground the SBB will act just like regular tugs but when you go on a slope it will even out the pressure so the cart isn't pulling strongly on one side of the saddle and causing the horse discomfort/imbalance. This means a smoother ride for you, less strain on the horse, and less torque on your shafts.
If you're considering a Smart Cart or anything with marathon shafts you may want to look into quick release tugs as well. They only come in stainless and make it MUCH easier to get your tug loops on those closed marathon shafts but work just the same for straight shafts as ordinary tugs do.
By the way, one of those British YouTube videos features photos I took of the Camptown mini SBB saddle at the 2007 National Drive! I found that kind of funny.
Leia