Just replaced my 15 liter GIVI tankbag with another same size GIVI , the zipper on the original one completely failed after about 90,000 miles. I was hoping to find a bag with an improved zipper but didn’t find anything that I liked so bought another GIVI with tank ring mount. Many years ago I had two different magnetic mount bags and they both worked nice, never noticed any scratches.
Other than the zipper issue I have been very satisfied with the GIVI bag. The handlebar does slightly touch the Tankbag on full lock left turns but it doesn’t have any effects on my riding.
That $99 magnetic Chase Harper bag does seem to be a nice quality item and it’s only slightly smaller than my GIVI , I might have considered one if I had seen it when I was buying. I will never buy a tankbag that requires messing with straps to secure it to the tank.