I can only answer (my experience) on the question of whitehill. I replaced this year my old heads for my 6 Head for running flooring/T&G and "V" Lining. They are replaceable tip variety and Whitehill custom ground cutters to my spec as I run specific thickness/width and have my own corporate shape for my product line. I had one issue with first tips supplied as they were too soft and seemed to break rather easily. This was quickly rectified with new tip with stronger strength to match my materials being run and faster speed (forget what the different material was sorry). Whitehill keep my profile on file and I can phone up and receive new tips very quickly. I cannot speak highly enough of replaceable tips over my solid profiles 2/4 wing I used before. Finish is outstanding and the setup/changeover is easier now in head/moulder since purchasing a Weinig CNC Powermat from my previous Unimat.
I have some other Whitehills on my Spindle/CNC Router and they are replacement tip as well and can do both due to matching tool holder chucks. Pity Weinig have there own tool chuck specific to them. I did hear this could change with the aquirement of the CNC Router company they just took over, match heads across their ranges, why oh why they should not have thought of this is beyond me, its like BETA and VHS in video.
But to be honest I have not had much problem with heads from any supplier, just how long you wait. Lietz (great CNC ideas) seem to take forever to supply so I stay clear of them and the Leuco 6 weeks for example (good light heads well made) have varied two and four wings in my stock cutters.