I'm a fairly new rider and we only ride on trails so after much research I ordered an Aussie saddle. I love it, I always feel so slouchy in a western saddle and I definitely feel secure in my Aussie. The other people I ride with will complain about being sore on a long ride when I'm still comfy.
I bought a cheap, used one initially and my horse hated it. Then I searched around for a while and bought one on line and sent in a whither tracing so I was sure it would fit. Check out
www.downunderweb.com. That's who I bought from - they give you lots of fitting help and have wonderful customer service. My horse seems to like this one pretty well and I think it fits her quite nicely.
Also, check out anything you think you might buy on
www.horsetackreview.com. Australian saddles aren't for everyone, my husband isn't a fan. I think some of the online stores will let you "rent" a demo saddle to try out, you just pay for shipping, but I'm not sure.
Call the different companies and ask lots of questions - I think I called 3 or 4 different ones and they were always happy to help!
Good luck!
Sarah