I had no previous model STM; it is in my opinion a step up in quality and optical comfort. The images are beautiful, so well-stitched, contrasting proportionately worthy of L. series goals Testing press reports are also complimentary. The development STM on my old 600D is stirring as hyper fast and totally silent The construction is all plastic including the bayonet but very good. It is less tough than metal but it has the advantage of lightness always nice vacation The main limitation is opening a fair bit in low light but for the price you can not have everything; in interior picture I used to compensate a small flash in indirect light that allows me to make beautiful portraits. Of course it does not come with a lens hood (mean = Canon) and is not compatible with full-frames what to consider if you are planning a future evolution towards large format, unlikely for me because then we change universes issue size, weight and price.