Hello catann,
I would like to give my opinion and you can do whatever you want with it.

I had one breast that had 3 tumors and 1 mass of unknown origin (?) and together they spanned from the 6:00 o'clock position all the way around the outside of my right breast to the 1:00 o'clock position. I opted for mastectomy on BOTH sides with immediate replacement with silicone implants. That means I would never need to come back for a cancer in the other one in the future.

Also, it would be one surgery, one insurance claim, two matching breast implants of equal size, matching equal scars, and only one recovery. Plus, no more mammograms, MRIs or biopsies or pokes or prods or worries about the remaining good breast in the future.
Removing that worry and that dread of recurrence in the other breast was important to me, and so it was a 'One and Done'. It has now been 25 months since surgery and I am doing fine and have a nice set of matching breasts that look very nice in clothes and not too bad naked, if you don't mind the single 4.5 inch-long scars on the sides of each breast.

Why choose implants over an autologous fat & tissue transfer? Well, I'll tell you why I did. First, I am a researcher and read everything I could get my hands on and learned everything I could before coming to my decision. I learned that removing tissue from one part of the body and moving it to another is not so simple.

The donor site will have quite a bit of surgery and will be vulnerable to infection and be painful and require care and recovery.
Also, removing large areas of tissue and fat may cause the donor area to look abnormal and deformed, rendering that part of your body unsatisfactory and a source of disappointment. (We have this fantasy that we will remove that spare fat around the hips or the waist and put it in the breast getting a 'Two-fer'). The truth is, that is not what will happen. The preferred technique to liposuction fat for aesthetics, will damage the fat cells, but preserve the aesthetics. The technique to harvest fat and tissue for reuse is focused on preserving the fat integrity and not so much on the aesthetics of the area you are removing it from, if you follow. It is more invasive and will leave large scars and depressions unless you have a very skilled surgeon with much experience in this technique.

Additionally, the donor fat and tissue can sometimes fail to develop an adequate blood supply at its new location, thus requiring multiple attempts. Even when successful, the transplanted fat can develop granulomas which are opaque can be mistaken for potential tumors on an MRI.

Also, there is the issue of shape. Trying to approximate the breast you had with the tissue from your abdomen, flank or thighs may look different from the breast you were hoping for. Sometimes, more surgery or liposuction and injections must be made, to get the shape and size approximation you wish. It may never look like the other breast. Only you can decide if that matters to you, and how much pain and recovery you are willing to go through to create a 'non-implant' breast.

Remember, you will be creating a wound in a healthy part of your body and will have two locations of injury rather than just one.
I say, why deface and injure another part of your body if you don't have to? It is a much simpler procedure to place a perfectly sized and shaped breast implant in the space of your former breast and just recover from that. I think I know that you were hoping to avoid the potential issues that breast implants present, but they truly can last a very long time (20+ years) if you take care of them.

I hope this was of some help. Only you can decide what is best for you. Do lots of research and satisfy yourself.
Good luck.