No experience with Toulouse, but extensive experience with Pessoa.
The AO is a great saddle. You will hear/read much about the quality going down in Pessoa since the move to Argentina in 2000? however I feel the quality is nice. What I do love about Pessoa is their unparalleled customer service - lifetime warranty on trees, and if you have a problem with the materials/craftsmanship, they really stand behind that also (within reasonable amount of time, of course - if your saddle is 10 years old and wearing in the seat, no).
I think their balance is wonderful, but that said, a saddle is an intensely individual purchase. You should try both if possible before you buy!
Check Rick's Heritage Saddlery for their remaining clearance Pessoa saddles ("like new" translates as new, discontinued saddles).
If you find one that fits you & your horse, the build on these saddles is superior.
For Toulouse saddles, contact Lynda at Classic Saddlery - she knows her saddles & will be able to help you with fit & her company always has great deals on the MT's.
Most of the threads about Toulouse saddles on this forum aren't very positive because the consensus leans toward high-end, expensive saddles, especially French ones. That's great if you can afford it, but IMO the Toulouse is a good, inexpensive saddle.
I bought one, a Noelle, for my daughter several years ago for a hard-to-fit gelding we were leasing. The saddle is very comfortable and looks extremely handsome after three years of moderate use.
Our B/O uses them on her school horses. These saddles receive very heavy use and indifferent care. The kids love them and fight over them. They have held up well after about 6 years of heavy use.
As for the Celine, I have never ridden in one, but I know they are popular. One of the boarders at our barn has one, and she loves hers. It's a nice-looking saddle.
I have a Pessoa (not AO, but a similar model) that was made in those few iffy years and I didn't like it for awhile but it actually broke in very nicely and I LOVE the saddle now. All of the one's I've sat in have been very balanced and comfortable without all of that cushy stuff that makes you sit 2 feet above your horses back. Personally, I don't like Toulouse saddles at all, I would definitely go for a Pessoa.