I've had an ICD since January of 2009. So far so good!
Pro-side: if you were to have a cardiac arrest your survival rate is over 99% successful with the protection of an ICD. Con-side: if you were to have a cardiac arrest outside of a hosptial your survival rate is around 5% without the protection of an ICD.
As effective as ICDs are they come with some risks such as infection after implant, device or lead malfunctions leading to further surgery, anxiety of being shocked, not being able to drive after a shock and some physical limitations.
I don't know off hand the actual percentage of serious complications of having an ICD but I do know that it is quite low now. ICDs are even being implanted in very young children.
In my personal opinion the benefits far outweigh the risks. If your doctor has offered one to you there is a very good chance that you may need it to save your life one day.
Good luck and take care,
I got my first ICD implanted in 1991, My second one saved my life in 1995. I have to agree with everything stevie_wonder said the benefits outweigh the risks.
I have had one installed over two years and they do give you a sence of security. I have never been shocked. Mine also is a pacemaker.