I have over 100 hours on my flex and as stated only use it for one steps so, my opinion is not one of a person who has not extensively used the flex.. In my eyes the finish my rotary produces is superior.
Does is do great work = heck yes, will most people be satisfied with it, yes can I see a noticeable difference in finish, yes...
Maybe I am just not as smart as most but the way I see it a jiggiling motion will never create a perfect finish as compared to a circular movement.
Although you may not think you see it I am fairly confident that the jiggling motion by nature creates microscopic inclusions that while may not be noticeable to most, does detract from the over all reflectivity (refraction) when compared to a rotary.
1. I assume you have not looked at the surface processed correctly by Flex and rotary under microscope to be able to say with 100% confidence there are "microscopic inclusions that detract from overall reflectivity". Am I correct in my assumption?
2. I assume you haven't measured reflectivity of the surfaces procssed by rotary vs Flex to be able to make firm statement which method results in higher reflectivity. Am I correct in my assumption?
3. You are forgetting that 3401 is not "jiggling". It has rotary component too.
4. Last, but far from least, laws of physics dictate that overall reflectivity is maximized when surface is reflecting light to maximum in all directions. It is a common sense random orbit will give better uniformity to surface, thus higher reflectivity, in that regard. Those that do not trust that and do not have access to expensive equipment can do simple test themselves and get an answer for themselves:
Take piece of wood and imagine that is your clear coat/paint. Now sand it with rotary sander. It sure removes wood fast but no matter how hard you tried to make it uniform you will notice once you drag fingers across surface that it is still relatively "rough". "Rough" surfaces sure do not result in maximum reflection.
Now take a random orbit sander to same surface, repeat same process and same test. Much smoother under your fingers, isn't it? And we all know laws of physics dictate that flatter (smoother) surface will reflect more.
Thus we have just proven that surface properly done with random orbit should result in higher reflectivity than one with pure rotary action. Unless there are those vague "microscopic inclusions".
But those "microscopic inclusions" you are venturing to assume might be there, could it that your assumption is based on experiences with PC not breaking down the polish and you could be forgetting 3401 is not the PC, neither by power nor by design? When was the last time you have seen anybody reporting "half moons" or anything like that with Flex? I have never. What about you? Have you seen them during your use?
I wish I had access to reflectometer and microscope so I can bust this myth once for good. If I had it I would also love to test few of my theories about roles of orbit size and path pattern type.