I can't comment on the specific oils you've mentioned, but I can say that Belray Thumper is about the best gearbox oil I've used, (even though it's an engine oil).

When I had my KTM525, (which has the normal engine oil setup running through the trans) I noticed that the gearbox was much smoother on Belray Thumper than the mega dollar Motorex fully synth 4 stroke oil.

I pulled the trans oil out of my RGV and put Belray Thumper in there, and again found a noticeable improvement.

I've heard some good things about the Motul oils, but I reckon they're overpriced. I prefer to run oils that are slightly less expensive, (not cheap) and change them more often.