I actually like the removable cylinder better. It is a cleaner, stronger design. If you want to consider the ability to reload, the Sidewinder *might* have an advantage...but really, if you're needing to reload your mini, then your day is likely ruined anyway.
Actually, replacing a spent cylinder with a fresh, FULL cylinder may be quicker than ejection and reloading of a swing-out cylinder.
I like the Sidewinder design and it is beautiful and collectable, but i don't see it as an improvement over the old design for purely self defensive considerations.