1997 Jeep Cherokee Transmission Repair

I have a 1997 Jeep Grand Cherokee that has 177k miles. I have been told that the transmission needs to be rebuilt. The place I am getting it repaired at was reccomended by my machanic, whom I like very much and am always happy with his work. The mechanic at the transmission shop drove my car and did an electronic diagnosis. He said that he has rebuilt Jeep transmissions before and he knows the minimum amount of parts & labor will be $1,100 but it could be as much as $1,600 once he gets a look at the transmission and sees if any other parts are damaged and need to be replaced. I just want to know if this sounds like a resonable price. Also, I am terrified of the stories I hear about people getting their transmission rebuilt and still have problems. What can I do to protect myself? Thank you!