I needed to purchase some some specialty tapered End Mills from Harvey Tool and was considering trying out some of there TiB_2 variable helix End Mills in 1/8" and 1/4" diameters when I place my order. At 26 and 33 bucks respectively, I'm wondering if their performance could possibly justify the additional cost? Especially considering the fact that the manufacturer's recommended SFM (1400) is WAY faster than a Tormach can hope to achieve. For the 1/8th EM, a tormach maxes out at 166 SFM, which seems like it might just rub and destroy the cutting edges. I'd be using them for both finishing and slotting in some small aluminum pieces.

Has anyone tired out any of these "fancy" End Mills? What would the effect of running an End Mill at a 10th of the manufacture's SFM be?