I have one! I love it! It makes you feel more connected with the horse and it fits most horses, I just throw it up on Dozer and it fits him fine(Dozer is my big draft), I use to put it on Tater(an appy) and it fit him as well. I think you should try it!
I have a Bob Marshall and LOVE it! Very comfy, great quality.
Other good brands that have western models include Ansur, Freeform, Sensation, Barefoot, and Black Forest. The last two are the most affordable. I have an English version of the Black Forest and it's nice quality for the price.
Stay AWAY from Hilason, Sydney Saddleworks, Maya, and any no-name or cheap eBay brand.
Just keep in mind that with any treeless saddle you will need to get a substantial saddle pad. I use a Skito Saddle pad with mine, the full treeless version. Skito pads are one of the most popular for treeless saddles. Other popular pads include Equipedic, Haf, Saddle Right, and Supracor.