It's a gamble since the procedure itself involves dealing with skin, blood vessels, nerve endings, and depending on the surgeon's skill it can go well or end up as a medical disaster. Quoting Dr. Wikipedia:
"The aesthetic, sensational, and functional results of vaginoplasty vary greatly. Surgeons vary considerably in their techniques and skills, patients' skin varies in elasticity and healing ability (which is affected by age, nutrition, physical activity and smoking), any previous surgery in the area can impact results, and surgery can be complicated by problems such as infections, blood loss, or nerve damage. "