I've got a Circle Y Arabian saddle and a couple of DownUnder Australian style saddles (in different sizes).
A genuine Australian saddle starts at around $2500 and goes up quickly, so most are out of my price range. The ones made outside of Australia are usually made in India, with varying degrees of oversight. The DownUnder saddles can usually be bought at a discount at around $750-800 new.
Compared to a western or English saddle, they don't compare to a Bates or Circly Y - but then, they don't cost as much either. On mine, the leather was decent for that price but needed oiling (or Passier Lederbalsam, which I prefer). The stitching is coarser, but durable enough.
In design, they feel more English than western. At least, the ones with serge panels do. The fleece panels are made more like a western saddle, and I don't know how they feel. The DownUnder folk strongly recommend I go with serge panels for my Arabians. They have a wider twist but the suspension seat is nice.
I dislike the Australian girth. It puts too much bulk and buckle under your leg, and the flaps tend to wear on the underside because of it. You can convert them to a western cinch, but you probably won't have enough circumference with an Arabian to do that. I know I don't, because I've tried. Mia is 15.3 hands and 900 lbs, for reference.
I like the security. The poleys work great. You can get them with or without a horn. I've got one each, and prefer without a horn by a small margin.
One thing I dislike are the long flaps. The long double flap and the odd girthing between creates too much bulk between me & the horse.
If I had a Quarter Horse, I'd prefer a western saddle overall. I think they are about equal for comfort and security, and the western saddles are better quality for the dollar and easier for me to use leg. However, I'm finding it tough to find a good western saddle that will fit my Arabians.
If at all possible, borrow one before buying. It seems to be a love/hate thing. My youngest daughter rode one a couple of times and swore she would never get in another. I like them, but I don't like their prices.
Oh, and they are sized pretty close to English. I ride in 17.5 and 18 inch English saddles, and prefer an 18 inch Australian - although I can squeeze into the 17 inch one my oldest daughter uses.
You can find a lot of reviews listed here: Trail Saddles