I had one just like it in black. The blue on the bottom is a sign that its a cheaper saddle. Usually the good ones have a tan-ish colored bottom. I would go to your local tack shop and have them check the tree for you, a lot of times the cheaper saddles are built with crooked trees. It can through off your balance and put pressure points on your horse.
On another note the cheap one I had was extremely comfortable and I enjoyed trail riding in it. The tree was a little weak, but wasn't crooked. The rigging was a little weak, and my breast collar pulled the seams out a bit, but it held up. I rode in in on a weeked trail ride, over 50 miles, and it worked great.
If you didnt pay much for it, its a good stater Aussie saddle. New, they cost about $300-$400.