Comparing to a "stihl bar" is a little hard without knowing what bar you comparing it to most stihl bars are laminate construction and so it's sort of an apple's to oranges deal. Lets take the most comparable bars a stihl rollomatic super E and a cannon super bar. The cannon has a better centered driver grove and a better surface finish inside that grove, the cannon bar has more spring back ie if you bend or flex the bar the stihl bars are much more likely to retain some of that bend and you will need to spend some time hammering it back straight where the cannon will likely be unscathed. In my experience the bar nose also has better fitment on the cannons, less gaps and misalignment where it meets the bar rails.
the supermini has a smaller nose (smaller kickback zone) if that's what you are wanting, if you are only buying it for sizing I would suggest you look at tsumuras as they have very good quality (ground not milled) and a good range of sizing and fitments for slightly less money than the cannons.
all that said the super mini is a very good bar if you have a reason for the smaller nose ie: plunge cutting, limbing, or carving. I run one on a ms261 and am on my second nose with basically the same grove dimension as a new bar
