>I was quite surprised at how sharp it was at 300mm, I was expecting it to be soft. There are a lot of internet myths - one of them is about "soft lenses". Generally at f8 and f11 there is little difference in sharpness and resolution in a 20 inch wide print between most lenses. I am not saying at 24 inch wide and bigger prints, or viewing at say 200% some differences cannot be detected, most noticeably at f5.6 compared to the ten times the price 300 f2.8 at f5.6. This zoom at 300mm is good for most photographers needs - as you have discovered
Photography is a bit like archery. A technically better camera, lens or arrow may not hit the target as often as it could if the photographer or archer does not practice enough.