I had an L5-S1 microdiscectomy. The disc had been herniated for about 6 years and had adhered to the sciatic nerve root, so every time I bent or twisted at the waist, the disc pulled on the nerve root causing muscle spasms and shooting pain down my leg.
The surgeon recommended a fusion since there is little actual flexibility at the L5-S1 disc anyhow, but he also offered a discectomy as a less invasive option so I took the discectomy.
It was successful in the sense that I am no longer crippled, however the disc is not entirely stable there and I still have some pain. The surgeon said that the inevitable scar tissue in the area would probably give me some pain for the rest of my life. But it's a success because my quality of life is greatly improved even though occasionally it goes out and really hurts bad for a day or two.
Looking back on it, I still don't know if a fusion would have been a better idea. Overall I think the results of a fusion would have been better but it would have had more potential negative impact on my career. As it is, I have some pain but I still have my job too.
Disc replacement is pretty new, but supposedly it can be pretty effective. Discectomy can be effective too but it may lead to instability and you might end up having to follow it with a fusion. Fusion can be successful but it's also not a 100% solution and it also increases the chance of injury to the discs right above and below the fused one.
I think the current research says that if you can rehab out of the crippling pain, your overall success and satisfaction of the treatment is statistically about the same as if you have surgery. Of course, if rehab doesn't work and you must do something to get back the quality of life you want, then you gotta pick a surgical solution. Just realize that there is a huge variety of results. You might end up pain free for life, and have no further complications or injuries. Or the surgery might not work, you might injure more of your back, and you might end up on a painkiller drip for the rest of your life. So you have to aim for a satisfactory quality of life and do whatever you have to do in order to achieve it. But very few outcomes involve 100% removal of pain or complete "fixing" of the problem.