I'm sorry to hear of your difficulties with neuropathy. Fortunately, it's not something i've had to deal with yet.
I've been on metformin for nearly 5 years now w/o any problems. It's helped with my insulin resistance and keeps my blood sugars in line.
There are side effects to any medication, even aspirin. While metformin could have contributed to your neuropathy, diabetes in general affects various systems in our bodies, and we have posts from many people over the years who have seen great results from it.
I think this is one of those instances where the statement "your mileage may vary" is very true. For me, the benefits of metformin have far outweighed any negatives, though I can certainly see why your situation would make you feel differently about it.