I was just wondering how many of you put faith in G-Wizard for calculating speeds and feeds?

I broke 3x 3mm bits over the last week so thought it was time to get a bit more technical about it. However, I notice that what G-Wizard suggests is different from what I have read on this forum, mostly it uses higher spindle RPM. For example I know Jonathan likes to cut aluminium using a single flute 6mm bit at 8000RPM and 600mm/min. However G-Wizard suggests more like 13000RPM. Though actually I just noticed now, it suggests pretty much what Jonathan said for an HSS cutter instead of carbide.

I broke my 3mm cutters on acrylic. I understood that it is best to have quite a high feed rate and a low RPM or else the plastic can melt. However, G-Wizard suggests that for a 3mm cutter with 3mm cut depths, I should use 22000RPM (!) and 770mm/min. IS this what you would expect, or is it going to melt the plastic? I haven't tried it yet as I need to get more 3mm bits, lol!

I also notice that it never seems to use more than about 0.2KW of cutting power which seems a little odd, do most tasks really need so little? Additionally it seems to love TiALN coated cutters but I thought that only really made a difference for really hot milling applications, not cutting plastic for example.