Mandy I can tell you the story of my girl.
I'm probably repeating myself but she was 7 (large breed gun dog) and started limping. Quick xray after a few days of pain killers only to find huge hole in the tibia. At this point, even though it was a few days, she was not putting her foot down and was in considerable pain. She has never been a drama queen so I knew that it must have been bad.
We also did chest xray and it was clear. My vet gave me the same choices. Having had chemo myself, I knew that I would not put her through it and I knew that there was no way she would sit through that, while it was administered. I have known other dogs that have had it though and coped well and it has given them a quality of life. But it wasn't for us.
My vet gave us 4-6 months, but did say there is always an exception to the rule. He was concerned that she would not cope on 3 legs but she had done up till that point, so she went in for surgery. After a couple of hours, he rang me and said I can go and get her cos she was barking to come out. ;) So he opened the kennel door when I got there, and she ran out, made a fuss of me and stood by the door while I paid. She was wide awake and itching to get home. I came home with loads of ab's and pk's and I opened the surgery door and she ran out, straight to the back of the van and waited for me to get there. The vet then said to me, she will cope!
So we went home and she slept and the swelling did get quite bad but after a few days she was improving. She wanted to come for a walk so we went and sat up on our local field and she just mooched about as she wanted to, and strenghening the other leg at the same time. I bought a harness from canine chemist for her (they do front and back end ones) so if she was tired, I could pop it on and carry her in it like you would a shopping bag. We did have one incident when somebody elses dog ran in to her and caused her op site to start bleeding but we popped to the Vet and it was just mainly old blood that had sat between the muscles so once it was all out, the swelling went right down and at that point, we turned the corner.
I met a lady who had a rottie x that had his front leg amputated as result of a traffic accident, and that was a male. He also managed to cock his leg too, which amazed me. She did warn me that people do make comments etc but I was all ready for that.
Since then, now 4 years down the line, she is still going. I know she is in the small minority that do survive but I was so pleased that I made that decision. The only thing she can't do now, that she did before is counter surf and open door handles. I did feel guilty at first because of the swelling etc but she soon got over it. Once the leg was gone, and she didn't have to carry the extra weight about, she just improved every day.
I do help her up the stairs now cos of her bronchitis but that has only been for the past 6 months or so. She got up on her own till then.
Over the years, people have commented, - 1 person asking me 'how much the op cost and saying that I could have bought 2 more dogs for that price' to which he got an answer that he wasn't expecting! Most people have been lovely and everybody knows her in the park where we walk.
We met a little boy who was about 7, playing football a couple of weeks ago on our local park and he was asking me all about the dogs etc. He asked me who was the slowest, oldest, fastest etc so I pointed at my old girl and said she is the oldest and the slowest now, and he asked why. So I said, well she is older than you and she only has 3 legs. He looked at her and asked if he could say hello to her. So he went over and said 'why does she have 3 legs, I've never seen a dog with 3 legs before'. I said, 'well you have now and she had it taken off my the Doctor cos her leg was poorly'. I had to smile because he went over to her, put his hand on her back and leaned right underneath her to have a proper look, just like you would if you where leaning down to check your car tyres. She just stood there while he examined her. It was amusing. Then came the inevitable question ' how does she wee'. :) So I just said, well she wee's like any other dog and he toddled off!
Anyway, I'm waffling now so thats my story. This site might be of help to you, in your decision. http://tripawds.com/
Have a browse through that.
My dog had no hang ups about her having her leg amputated, she was just back to normal in a few weeks, and free from pain, and more importantly she was still here with us.