I have an Abbott stimulator for about 1 1/2 years (placed before any surgeries). I had the smallest unit they made implanted as I am small and fairly thin. You can feel where the leads are in my back and easily see the battery pack. They bother me when I sit against something hard where the leads are but it's more of an annoyance rather terribly painful. Mine is one I have to charge as the rechargeable battery was much larger. I only have to charge about every 2 months so that is not really an issue. The real problem is that it hasn't helped. I am scheduled for a major back surgery in February and the leads will be removed. I was told when I did the trial, I would be able to do everything I wanted to do to test the stimulator, but when the leads were placed temporarily, I actually couldn't do much or it would have been pulled out and wouldn't work so the test was useless in my opinion.
My father-in-law had a stimulator and did feel like he got some relief. He had had three failed back surgeries.
Good luck getting some relief.