I have one and LOVE it! They do tend to run a tad small, 1/2" to 1" smaller than a traditional western saddle IME. Some people say they run true to size though. I think it depends on what kind of western saddle you're used to riding in, lol.
The pommels do need to fit the horse. The Barrel and Trail model pommels have QH bar type angles. The Endurance pommel is more like Full QH bars. You do have some room for error though as there isn't as much weight coming down through the pommel as a traditional treed saddle. I have used my endurance model on everything from wide tanks to high withered gaited horses with good success. I just used a couple of shims in my Skito pad for the high withered horses.
Yes, you DO need a pad specficially designed for a treeless saddle. The BMSS does not provide any weight distribution or spinal clearance on its own. Popular pads for BMSS saddles include Skito
(the most popular), Equipedic
, Toklat Ultracell Woolback
, ThinLine ProTech pad
w/extra shims, and Supracor Reining/Roping pad
. You need a pad that has a clear spine and good weight distribution.
Skito has come out with a new "half pad" designed for treeless saddles. It's more economical and you can use pretty blankets under or over it if you show or just have a saddle pad fetish, lol. Tack - Saddle Pads - Skito Pads - Skito Treeless Half Pad - Interpad - Arete Equestrian - Half Chaps, Skito & Supracor Saddle Pads... - (Powered by CubeCart)
I am a heavy weight rider (250 lbs), so I use a Skito pad and a ThinLine pad together; on of the simple ThinLine Western pads
. The extra pad under the Skito provides more weight distribution and is VERY non-slip. I feel quite secure in my saddle, even on green horses or "fun" trail rides. I use a 100% mohair roper cinch for added stability. For trail riding, I use an over-the-neck aussie/english style breastcollar (we have lots of hills!).
Here's my set up.
I swapped out the regular stirrups for padded, caged endurance stirrups. I have no problems keeping my leg under me for a "classical" position.