Most users will admit that the Super Fly will produce a nice surface finish. Particularly in aluminum.

Wanting to be able to be a bit more aggressive, and have options for the inserts used by the Super Fly I looked around and found a 1" 2 flute face mill from Shars with a 3/4 inch shank. I have used both for the same jobs on the Tormach mills. For some jobs the face mill can definitely be used more aggressively for faster completion times, but on a job I do routinely back facing a part I found one tool was definitely better than the other.

The part sets in step jaws in the vise. Each side has two flats and a round that should ideally be able to clamp nicely in the jaws, but in practice I got a small flat from clamping pressure on the round. It was ugly. In order to mitigate that I set up the part so the round was partially supported by the step in the vise jaws, but hung off far enough so that it was not quite clamped in the vise jaws. No more flat spot. Unfortunately when I tried to aggressively back face the part I got pretty bad chatter and an interesting jewelling of chatter marks on the part. Even backing it off to Super Fly speeds and feeds it still chattered. With the exact same setup I ran the Super Fly and got a clean wonderful looking part with zero chatter.

In conclusion for modestly heavy roughing with a well supported and fully clamped part the little face mill may be marginally better, but for a part that may be fully supported, but not necessarily fully clamped the Super Fly is definitely better.