My wife had the full transplant conditioning. She had an unrelated donor transplant in her 40s. Her story is
here.
The National Marrow Donor Program has
summaries of myeloablative or non-myeloablative conditioning regimens but doesn't give guidance on making the choice.
Non-myeloablative conditioning first got attention as a way to offer transplants to older patients (60s, 70s, or higher). Having an easier conditioning regimen produced better transplant survival rates, but patients had a higher relapse rate. Older patients or patients in generally poor health often didn't have any choice. When to use non-myeloablative conditioning for younger or otherwise healthy patients is more subject to debate and study. Much of the data we have is from years past, so it might be worth asking the study leaders if they can provide you with recent statistics on the differences in outcomes for patients who match your age and health condition.