My 95lb malamute had the full TTA after she fully tore her ACL. The cost is high, but it all depends on your financial situation/dogs age/etc. I am glad we did it, even though it was A LOT of work right out of the gate. The hardest part we had was the first day after the surgery and the dog being in a lot of pain - they give you some pretty strong painkillers which help, but the dog will be hurting when the next dose is due for a while.
The second most challenging part was getting her to go to the bathroom for the first time after the surgery, they will have you either use a bedsheet or a specifically made sling to hold up the dogs rear end and to keep all the weight off of the leg. The will eventually get use to it, but figuring it out that first time is not the easiest thing. For our sling, I started using a bedsheet, but then switched to using a firewood sling - the firewood sling was AWESOME (and cheap) compared to the slings they try to sell for $60+.
Overall, I am very happy with getting it done. The dog made a full recovery and is as active as she use to be. The recovery process is very involved with PT, and if you stick to it the dog will do great.