Need Info on Medtronic Implant

I keep meaning to ask...

Does anyone have any info/opinions on the Medtronic Spinal Nerve Stimulator? My Pain Mgmt clinic wants to implant one. I've been to the website and the BBs and can't form a good opinion. I can't stand to use a TENS- the sensation drives me nuts, yet the info I've found discribes a 'tingling sensation' along the nerve path when activated.

After 4 back surgeries I'm not inclined to agree to something that doesn't have a good success rate but I hate to form a negative opinion before the trial as the next option is an implanted MS pump.