I used it to attach my new lower rear quarters and it worked great. Seemed much easier than spot welding those panels in place. I did use a few self tapping sheet metal screws to get the panel aligned in place, then removed it, applied adhesive and then ran the screws back in to hold it secure.
I used a 3m product, not cheap ($40) and also required a "double tube caulk gun" to apply it ($75).
I picked up both items at a local auto paint supply place.