I won't forget my friend of mine, who from the beginning preferred Linux over MOS (before getting his Peg), and now refraining "Why is it so damn slow?" when he boots into Linux instead of MOS. I've heard from him "Voyager is the fastest browser on earth" and the like, when he tried MOS. Again, it's nothing objective, just the result of the shock having an AmigaOS like operating system on a decent hardware. The same will go for OS4 I presume.
Except stability AmigaOS is a killer. Stability is the issue both OS4 and MOS will have to face, and they address differently.
I know, I know, a decent browser provides more than current Amiga browsers, just as Linux provides more services than either OS I mentioned above but I hope you get what I mean. :-)